Simplify and express the result in power notation with positive exponent.
$\left( i \right){\left( { - 4} \right)^5} \div {\left( { - 4} \right)^8}$
$\left( {ii} \right){\left( {\dfrac{1}{{{2^3}}}} \right)^2}$
$\left( {iii} \right){\left( { - 3} \right)^4} \times {\left( {\dfrac{5}{3}} \right)^4}$
$\left( {iv} \right)\left( {{3^{ - 7}} \div {3^{ - 10}}} \right) \times {3^{ - 5}}$
$\left( v \right){2^{ - 3}} \times {\left( { - 7} \right)^{ - 3}}$
Answer
666.6k+ views
Hint – In this particular question use the concept that the resultant in power notation with positive extent is written as ${\left( a \right)^{ + n}}$ or ${\left( {\dfrac{1}{a}} \right)^{ + n}}$or -${\left( a \right)^{ + n}}$ or -${\left( {\dfrac{1}{a}} \right)^{ + n}}$ so use this concept to reach the solution of the question.
Complete step by step solution:
We have to simplify these expressions and we have to express the resultant in power notation with positive extent.
For example: we have to express in the terms of ${\left( a \right)^{ + n}}$ or ${\left( {\dfrac{1}{a}} \right)^{ + n}}$or -${\left( a \right)^{ + n}}$ or -${\left( {\dfrac{1}{a}} \right)^{ + n}}$.
Where, (a) and (n) are some positive constants.
$\left( i \right){\left( { - 4} \right)^5} \div {\left( { - 4} \right)^8}$
Now as we know that negative one to the power of odd numbers is always negative one.
And a negative one to the power of even numbers is always a positive one.
So first simplify the above equation according to the above property we have,
$ \Rightarrow \left[ {{{\left( { - 1} \right)}^5}{{\left( 4 \right)}^5}} \right] \div \left[ {{{\left( { - 1} \right)}^8}{{\left( 4 \right)}^8}} \right]$
$ \Rightarrow \left[ { - {{\left( 4 \right)}^5}} \right] \div \left[ { + {{\left( 4 \right)}^8}} \right]$
$ \Rightarrow - \dfrac{{{{\left( 4 \right)}^5}}}{{{4^8}}}$
Now use the property that ($\dfrac{{{a^m}}}{{{a^n}}} = {a^{m - n}}{\text{ or }} = \dfrac{1}{{{a^{n - m}}}}$), so we have
$ \Rightarrow - \dfrac{1}{{{4^{8 - 5}}}} = - \dfrac{1}{{{4^3}}}$
Now as we know that, $4 = {2^2}$ so we have,
$ \Rightarrow - \dfrac{1}{{{4^{8 - 5}}}} = - \dfrac{1}{{{4^3}}} = - \dfrac{1}{{{{\left( {{2^2}} \right)}^3}}} = - \dfrac{1}{{{2^6}}}$
So this is the required simplification of the first expression.
$\left( {ii} \right){\left( {\dfrac{1}{{{2^3}}}} \right)^2}$
As we know that the square of 1 is always 1.
Therefore, ${\left( {\dfrac{1}{{{2^3}}}} \right)^2} = \dfrac{1}{{{{\left( {{2^3}} \right)}^2}}} = \dfrac{1}{{{2^6}}}$
So this is the required simplification of the second expression.
$\left( {iii} \right){\left( { - 3} \right)^4} \times {\left( {\dfrac{5}{3}} \right)^4}$
So first simplify the above equation according to the above written property we have,
$ \Rightarrow {\left( { - 3} \right)^4} \times {\left( {\dfrac{5}{3}} \right)^4} = {\left( { - 1} \right)^4}{\left( 3 \right)^4} \times {\left( {\dfrac{5}{3}} \right)^4} = + {\left( 3 \right)^4} \times {\left( {\dfrac{5}{3}} \right)^4}$
Now again simplify we have,
\[ \Rightarrow {\left( 3 \right)^4} \times {\left( {\dfrac{5}{3}} \right)^4} = {\left( 3 \right)^4} \times \dfrac{{{5^4}}}{{{3^4}}} = {5^4}\]
So this is the required simplification of the third expression.
$\left( {iv} \right)\left( {{3^{ - 7}} \div {3^{ - 10}}} \right) \times {3^{ - 5}}$
Now in the above equation use the property that $\dfrac{{{a^{ - b}}}}{{{c^{ - d}}}} = \dfrac{{{c^d}}}{{{a^b}}}$ so we have,
$ \Rightarrow \left( {{3^{ - 7}} \div {3^{ - 10}}} \right) \times {3^{ - 5}} = \left( {{3^{10}} \div {3^7}} \right) \times {3^{ - 5}}$
$ \Rightarrow \left( {{3^{10}} \div {3^7}} \right) \times {3^{ - 5}} = \left( {\dfrac{{{3^{10}}}}{{{3^7}}}} \right) \times {3^{ - 5}}$
Now use the property that ($\dfrac{{{a^m}}}{{{a^n}}} = {a^{m - n}}{\text{ or }} = \dfrac{1}{{{a^{n - m}}}}$), so we have
$ \Rightarrow \left( {\dfrac{{{3^{10}}}}{{{3^7}}}} \right) \times {3^{ - 5}} = \left( {{3^{10 - 7}}} \right) \times {3^{ - 5}} = {3^3} \times {3^{ - 5}} = {3^{3 - 5}} = {3^{ - 2}} = \dfrac{1}{{{3^2}}}$
So this is the required simplification of the fourth expression.
$\left( v \right){2^{ - 3}} \times {\left( { - 7} \right)^{ - 3}}$
Now simplify this we have,
$ \Rightarrow {2^{ - 3}} \times {\left( { - 7} \right)^{ - 3}} = \dfrac{1}{{{2^3} \times {{\left( { - 7} \right)}^3}}} = \dfrac{1}{{{2^3} \times {{\left( { - 1} \right)}^3}{{\left( 7 \right)}^3}}} = \dfrac{{ - 1}}{{{2^3} \times {{\left( 7 \right)}^3}}} = \dfrac{{ - 1}}{{{{\left( {2 \times 7} \right)}^3}}} = \dfrac{{ - 1}}{{{{\left( {14} \right)}^3}}}$
So this is the required simplification of the fifth expression.
So this is the required answer.
Note – Whenever we face such types of questions the key concept we have to remember is that always remember that a negative one to the power of an odd number is always a negative one. And negative one to the power of even numbers is always positive one so simplify accordingly as above, we will get the required answer.
Complete step by step solution:
We have to simplify these expressions and we have to express the resultant in power notation with positive extent.
For example: we have to express in the terms of ${\left( a \right)^{ + n}}$ or ${\left( {\dfrac{1}{a}} \right)^{ + n}}$or -${\left( a \right)^{ + n}}$ or -${\left( {\dfrac{1}{a}} \right)^{ + n}}$.
Where, (a) and (n) are some positive constants.
$\left( i \right){\left( { - 4} \right)^5} \div {\left( { - 4} \right)^8}$
Now as we know that negative one to the power of odd numbers is always negative one.
And a negative one to the power of even numbers is always a positive one.
So first simplify the above equation according to the above property we have,
$ \Rightarrow \left[ {{{\left( { - 1} \right)}^5}{{\left( 4 \right)}^5}} \right] \div \left[ {{{\left( { - 1} \right)}^8}{{\left( 4 \right)}^8}} \right]$
$ \Rightarrow \left[ { - {{\left( 4 \right)}^5}} \right] \div \left[ { + {{\left( 4 \right)}^8}} \right]$
$ \Rightarrow - \dfrac{{{{\left( 4 \right)}^5}}}{{{4^8}}}$
Now use the property that ($\dfrac{{{a^m}}}{{{a^n}}} = {a^{m - n}}{\text{ or }} = \dfrac{1}{{{a^{n - m}}}}$), so we have
$ \Rightarrow - \dfrac{1}{{{4^{8 - 5}}}} = - \dfrac{1}{{{4^3}}}$
Now as we know that, $4 = {2^2}$ so we have,
$ \Rightarrow - \dfrac{1}{{{4^{8 - 5}}}} = - \dfrac{1}{{{4^3}}} = - \dfrac{1}{{{{\left( {{2^2}} \right)}^3}}} = - \dfrac{1}{{{2^6}}}$
So this is the required simplification of the first expression.
$\left( {ii} \right){\left( {\dfrac{1}{{{2^3}}}} \right)^2}$
As we know that the square of 1 is always 1.
Therefore, ${\left( {\dfrac{1}{{{2^3}}}} \right)^2} = \dfrac{1}{{{{\left( {{2^3}} \right)}^2}}} = \dfrac{1}{{{2^6}}}$
So this is the required simplification of the second expression.
$\left( {iii} \right){\left( { - 3} \right)^4} \times {\left( {\dfrac{5}{3}} \right)^4}$
So first simplify the above equation according to the above written property we have,
$ \Rightarrow {\left( { - 3} \right)^4} \times {\left( {\dfrac{5}{3}} \right)^4} = {\left( { - 1} \right)^4}{\left( 3 \right)^4} \times {\left( {\dfrac{5}{3}} \right)^4} = + {\left( 3 \right)^4} \times {\left( {\dfrac{5}{3}} \right)^4}$
Now again simplify we have,
\[ \Rightarrow {\left( 3 \right)^4} \times {\left( {\dfrac{5}{3}} \right)^4} = {\left( 3 \right)^4} \times \dfrac{{{5^4}}}{{{3^4}}} = {5^4}\]
So this is the required simplification of the third expression.
$\left( {iv} \right)\left( {{3^{ - 7}} \div {3^{ - 10}}} \right) \times {3^{ - 5}}$
Now in the above equation use the property that $\dfrac{{{a^{ - b}}}}{{{c^{ - d}}}} = \dfrac{{{c^d}}}{{{a^b}}}$ so we have,
$ \Rightarrow \left( {{3^{ - 7}} \div {3^{ - 10}}} \right) \times {3^{ - 5}} = \left( {{3^{10}} \div {3^7}} \right) \times {3^{ - 5}}$
$ \Rightarrow \left( {{3^{10}} \div {3^7}} \right) \times {3^{ - 5}} = \left( {\dfrac{{{3^{10}}}}{{{3^7}}}} \right) \times {3^{ - 5}}$
Now use the property that ($\dfrac{{{a^m}}}{{{a^n}}} = {a^{m - n}}{\text{ or }} = \dfrac{1}{{{a^{n - m}}}}$), so we have
$ \Rightarrow \left( {\dfrac{{{3^{10}}}}{{{3^7}}}} \right) \times {3^{ - 5}} = \left( {{3^{10 - 7}}} \right) \times {3^{ - 5}} = {3^3} \times {3^{ - 5}} = {3^{3 - 5}} = {3^{ - 2}} = \dfrac{1}{{{3^2}}}$
So this is the required simplification of the fourth expression.
$\left( v \right){2^{ - 3}} \times {\left( { - 7} \right)^{ - 3}}$
Now simplify this we have,
$ \Rightarrow {2^{ - 3}} \times {\left( { - 7} \right)^{ - 3}} = \dfrac{1}{{{2^3} \times {{\left( { - 7} \right)}^3}}} = \dfrac{1}{{{2^3} \times {{\left( { - 1} \right)}^3}{{\left( 7 \right)}^3}}} = \dfrac{{ - 1}}{{{2^3} \times {{\left( 7 \right)}^3}}} = \dfrac{{ - 1}}{{{{\left( {2 \times 7} \right)}^3}}} = \dfrac{{ - 1}}{{{{\left( {14} \right)}^3}}}$
So this is the required simplification of the fifth expression.
So this is the required answer.
Note – Whenever we face such types of questions the key concept we have to remember is that always remember that a negative one to the power of an odd number is always a negative one. And negative one to the power of even numbers is always positive one so simplify accordingly as above, we will get the required answer.
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