Question

How many solutions does this linear system have

y = 2x - 5

-8x - 4y = -20

Answer 1

replace the 1st equation into the 2nd one for y

-8x-4(2x-5) = -20

-8x-8x+20 =-20

-16x+20 = -40

-16x=-40

x = 5/2 = 2.5

y = 2x-5 - 2(2.5) - 5 = 5-5 = 0

one solution (2.5,0)