Write the conditions in algebra. x = y + 2 3x + 4y = 8x - 20 From the first equation y = x - 2. Substitute for y in the second equation. 3x + 4(x - 2) = 8x - 20 3x + 4x - 8 = 8x - 20 7x = 8x - 12 So x = 12
You should always check your answers for simultaneous equations y = 10 because x = y + 2 3 x 12 + 4 x 10 = 8 x 12 - 20? 36 + 40 = 96 - 20. This is true!
For a multi choice problem it would be faster to just try each value until one works
