Question

How do you solve an equation using substitution$?$

Answer 1

Steps to solve a system of equations by substitution are as follows:

1. Solve one of the equations for either variable.
2. Substitute the resultant expression from step 1 into the other equation.
3. Solve the resulting equation.
4. Substitute the solution from step 3 into one of the original equations to find the other variable.
5. Write the solution as an ordered pair.
6. Check weather the ordered pair is a solution to both original equations.

For Example;

Let $x+y=-1$ and $y=x+5$ be two linear equation,

Put the value $y=x+5$ in $x+y=-1$, we get

$x+\left(x+5\right)=-1$

$\Rightarrow$ $2x+5=-1$

$\Rightarrow$ $2x=-6$

$\Rightarrow$ $x=-3$

Now, Put the value $x=-3$ in $y=x+5$, we get

$y=-3+5$

$\Rightarrow$$y=2$

$\therefore$The solution is $\left(-3,2\right)$

Hence, we can solve an equation using substitution method by following these steps.