Question

solve the system by substitution. 7x—3y= -25 4x+ 5=y

Answer 1

The given system is-

$\mleft\{\begin{aligned}7x-3y=-25 \\ 4x+5=y\end{aligned}\mright.$

To solve it by substitution, we just have to replace the second equation in the first one.

$7x-3(4x+5)=-25$

Now we solve for x.

$\begin{gathered} 7x-12x-15=-25 \\ -5x=-25+15 \\ -5x=-10 \\ x=\frac{-10}{-5} \\ x=2 \end{gathered}$

Then, we use x value to find y.

$\begin{gathered} y=4x+5 \\ y=4(2)+5=8+5 \\ y=13 \end{gathered}$

Therefore, the solution to the system is x = 2 and y = 13.