Question

Solve:
x^2 + y^2 = 25
2x - y = 5

Answer 1

from 2nd equation, y=2x-5

Answer 2

substitute y=2x-5 into the 1st equation

Answer 3

x^2+(4x^-20x+25)=25

Answer 4

now re-arrange and you'll have 5x^2-20x=0

Answer 5

so dividing by 5 gives x^2-4=0
x=2

Answer 6

now put x=2 into y=2x-5 and you'll get y=-1