How do graph $ x + y = 3 $ by plotting points?

Hint: We will solve this question by plotting points. First, we will assume the value of $ x = 0 $ , by applying the assumed value of $ x $ , we will get the coordinate of $ y $ . Then, we will assume the value of $ y = 0 $ , and we will apply it in the equation, by which we will get the $ x $ coordinate. Finally, we will plot the points in the graph.

Complete step-by-step answer:
Now, the given equation is $ x + y = 3 $ .
Let us consider $ x = 0 $ , by substituting we have,
 $ 0 + y = 3 $
 $ y = 3 $
Therefore, the point is $ \left( {0,3} \right) $ .
Now, let us consider $ y = 0 $ , by substituting we have,
 $ x + 0 = 3 $
 $ x = 3 $
Therefore, the point is $ \left( {3,0} \right) $
Hence, the points are $ \left( {0,3} \right) $ and $ \left( {3,0} \right) $ .
Now, let us plot the points graphically,

Note: We can also determine the points using slope-intercept form. The slope-intercept form is probably the most frequently used way to express the equation of a line. Equation of straight line is usually written in the slope-intercept form i.e., $ y = mx + b $ , where the $ m $ is the slope and $ b $ is the $ y $ - intercept. When we are given an equation in slope- intercept form, we can use the $ y $ - intercept as the point, then out the slope from there. When an equation of a line is not given in slope-intercept form, our first step will be to solve the equation for $ y $ . Sometimes the slope intercept form will be called as $ y $ -form.