How do you solve the following linear system? \[3s+4=-4t\],\[7s+6t+11=0\]?
Answer
610.8k+ views
Hint: From the question we have been given two linear equations and we are asked to find the solution. For solving these linear equations we will make one variable subject by taking one equation and after making the subject we will substitute that variable value in another given equation and solve the question.
Complete step-by-step solution:
Firstly, as we said before we will take one given equation and make the variable \[s\] as subject and write it in terms of another variable. So, the equation will be reduced as follows.
We will take the equation \[3s+4=-4t\] and make the variable \[s\] as a subject.
\[\Rightarrow 3s+4=-4t\]
\[\Rightarrow 3s=-4t-4\]
\[\Rightarrow s=\dfrac{-4t-4}{3}\]
Here we got the value of \[s\] as follows. Now we will substitute this value in the other given equation.
So, we get the equation reduced as follows.
\[\Rightarrow 7s+6t+11=0\]
\[\Rightarrow 7\left( \dfrac{-4t-4}{3} \right)+6t+11=0\]
Now, we will multiple the whole equation three on both sides. So, we get the equation reduced as follows.
\[\Rightarrow 7\left( -4t-4 \right)+3\left( 6t+11 \right)=0\]
Now, we will expand the brackets in the equation and simplify the equation using basic mathematical operations like addition and subtraction. So, we get the equation reduced as follows.
\[\Rightarrow -28t-28+18t+33=0\]
\[\Rightarrow -10t+5=0\]
\[\Rightarrow -10t=-5\]
\[\Rightarrow t=\dfrac{1}{2}\]
Now, we will substitute this \[\Rightarrow t=\dfrac{1}{2}\] in any one of the given equations in the question and find the value of the other variable.
We will substitute this \[\Rightarrow t=\dfrac{1}{2}\] in the equation \[\Rightarrow 3s+4=-4t\]. So, we get the equation reduced as follows.
\[\Rightarrow 3s+4=-4t\]
\[\Rightarrow 3s+4=-4\left( \dfrac{1}{2} \right)\]
\[\Rightarrow 3s+4=-2\]
\[\Rightarrow 3s=-2-4\]
\[\Rightarrow 3s=-6\]
\[\Rightarrow s=-2\]
Therefore, the solution is \[\Rightarrow s=-2\] and \[\Rightarrow t=\dfrac{1}{2}\].
Note: Students must be very careful in doing the calculations. Students must have good knowledge in substitution methods and basic operations of mathematics like addition and subtraction. We must not do mistakes in calculation like for example after this step \[\Rightarrow 3s+4=-2\] if we write the next step as \[\Rightarrow 3s=-2+4\] instead of \[\Rightarrow 3s=-2-4\] our solution will be wrong
Complete step-by-step solution:
Firstly, as we said before we will take one given equation and make the variable \[s\] as subject and write it in terms of another variable. So, the equation will be reduced as follows.
We will take the equation \[3s+4=-4t\] and make the variable \[s\] as a subject.
\[\Rightarrow 3s+4=-4t\]
\[\Rightarrow 3s=-4t-4\]
\[\Rightarrow s=\dfrac{-4t-4}{3}\]
Here we got the value of \[s\] as follows. Now we will substitute this value in the other given equation.
So, we get the equation reduced as follows.
\[\Rightarrow 7s+6t+11=0\]
\[\Rightarrow 7\left( \dfrac{-4t-4}{3} \right)+6t+11=0\]
Now, we will multiple the whole equation three on both sides. So, we get the equation reduced as follows.
\[\Rightarrow 7\left( -4t-4 \right)+3\left( 6t+11 \right)=0\]
Now, we will expand the brackets in the equation and simplify the equation using basic mathematical operations like addition and subtraction. So, we get the equation reduced as follows.
\[\Rightarrow -28t-28+18t+33=0\]
\[\Rightarrow -10t+5=0\]
\[\Rightarrow -10t=-5\]
\[\Rightarrow t=\dfrac{1}{2}\]
Now, we will substitute this \[\Rightarrow t=\dfrac{1}{2}\] in any one of the given equations in the question and find the value of the other variable.
We will substitute this \[\Rightarrow t=\dfrac{1}{2}\] in the equation \[\Rightarrow 3s+4=-4t\]. So, we get the equation reduced as follows.
\[\Rightarrow 3s+4=-4t\]
\[\Rightarrow 3s+4=-4\left( \dfrac{1}{2} \right)\]
\[\Rightarrow 3s+4=-2\]
\[\Rightarrow 3s=-2-4\]
\[\Rightarrow 3s=-6\]
\[\Rightarrow s=-2\]
Therefore, the solution is \[\Rightarrow s=-2\] and \[\Rightarrow t=\dfrac{1}{2}\].
Note: Students must be very careful in doing the calculations. Students must have good knowledge in substitution methods and basic operations of mathematics like addition and subtraction. We must not do mistakes in calculation like for example after this step \[\Rightarrow 3s+4=-2\] if we write the next step as \[\Rightarrow 3s=-2+4\] instead of \[\Rightarrow 3s=-2-4\] our solution will be wrong
Recently Updated Pages
Explain the Treaty of Vienna of 1815 class 10 social science CBSE

A Paragraph on Pollution in about 100-150 Words

What is BLO What is the full form of BLO class 8 social science CBSE

10 examples of friction in our daily life

Draw a diagram of nephron and explain its structur class 11 biology CBSE

Write structures of the following compounds i 2 Chloro3methylpentane class 11 chemistry CBSE

Trending doubts
Which is the Lowest Point of Earth?

Which is the hottest planet in the Solar system A Earth class 10 social science CBSE

Name any four life processes in living things class 10 biology CBSE

Identify the plural form of the word child from the class 10 english CBSE

Identify the feminine form of noun nephew a shenephew class 10 english CBSE

Write a factual description in about 100 words on class 10 english CBSE

