The equation 4x = y is solve for y so we can substitute the expression 4x for y in the other equation.
2x² - (4x) = 0 ← Substituted 4x for y...Hug'em when you plug'em (use ( )s) 2x² - 4x = 0 ← prepare to factor 2x(x - 2) = 0 ← factored out the GCF 2x = 0 or x - 2 = 0 ← zero product property x = 0 or x = 2 ← solved each mini equation If x = 0, then y = 4(0) = 0. (0, 0) is a solution If x = 2, then y = 4(2) = 8. (2, 8) is a solution The solution set is {(0,0), (2,8)}