Question

Put the steps in order that are used to solve the following systems of equations by substitution.

−7x−2y=−13

x−2y=11
(10 points)

Answer 1

1) Solve one of the equations for either x or y in terms of the other variable. In this case, we can solve the second equation for x:
x = 2y + 11

2) Substitute the expression for x from step 1 into the other equation.
-7(2y + 11) - 2y = -13

3) Simplify and solve the resulting equation for y.
-14y -77 - 2y = -13
-16y - 77 = -13
-16y = 64
y = -4

4) Substitute the value of y from step 3 into the expression for x from step 1.
x = 2(-4) + 11 = 3

5) The solution to the system of equations is x = 3 and y = -4.