How do i do solving systems of equations by substitution?

Step 1:Solve one of the equations for either x = or y = .

Step 2:Substitute the solution from step 1 into the other equation.

Step 3:Solve this new equation.

Step 4:Solve for the second variable.

I hope this helps!

5x+40

5(x + 8)

7x - 49

7(x - 7)

18x + 9

9(2x + 1)

15x - 10

5(3x - 2)

step-by-step explanation:

for number one all you have to do is factor 5 out of 5x + 40

for number 2 factor 7 out of 7x - 49

for number three factor 9 out of 18x + 9

for number four factor 5 out of 15x - 10

i think the answer is d im not sure