Chapter 8, Problem 20PT

To determine

To solve: the given system of equations by substitution.

Answer to Problem 20PT

The solution of the equations is: $\left(2,-1\right)$

Explanation of Solution

Given:

Consider the equations:

  $\begin{array}{l}y=2x-5\\ y=-1\end{array}$

Calculation:

First step is to replace y with $-1$ in the first equation.

  $-1=2x-5$

Add both sides of equation by 5.

  $\begin{array}{c}-1+5=2x-5+5\\ 4=2x\end{array}$

Divide both sides of equation by 2.

  $\begin{array}{l}\frac{4}{2}=\frac{2x}{2}\\ 2=x\end{array}$

Conclusion:

Therefore, the solution of the equations is: $\left(2,-1\right)$