Question

Explanation of substitution method through an example .

Answer 1

In the method of substitution, for a pair of linear equations in two variables, we resolve one of the equations for any one variable and substitute that variable in the other equation to get the solution for the other variable.
Let us take an example:
We have two linear equations
$x+y=20$..... (1)
$3x+2y=48$.... (2)
In the equation (1), we resolve it as
$y=20-x$..... (3)
Now, substituting equation (3) in (2),
$3x+2(20-x)=48$
$3x+40-2x=48$
$x+40=48$
Therefore, $x=8$
Putting value of $x$ in equation (1), we get $y=20-8=12$
Therefore $x=8$ and $y=12$.