2x + 8y = 20

-5x-20y=-50

System of Equations.

You can either substitute or eliminate a variable.

Substitue:

2x + 8y = 20

:2 : 2 : 2

x + 4y = 10

x = - 4y + 10 (plug this into the second equation)

-5 (-4y + 10) - 20y = - 50 (distribute)

20y - 50 - 20y = - 50

-50 = - 50

0 = 0

Ax + by = 12; 2x + 8y = 60. ax + by = 12; 2x + 8y = 60