Question

Solve by the substitution method. 4x+4y=20 -2x+y=11

Answer 1

Answer:

x = -2,   y = 7

Step-by-step explanation:

Since it's a system of equations, we know that the they use the same variables. To use substitution to solve a system of equation, we must take one equation and solve it for a variable, then you plug the solution into that variable for the other equation:

-2x + y = 11

y = 2x + 11

-------

4x + 4y = 20

4x + 4(2x + 11) = 20

4x + 8x + 44 = 20

12x + 44 = 20

12x = -24

x = -2

Then we can plug "x" into the first equation:

-2x + y = 11

-2(-2) + y = 11

4 + y = 11

y = 7