what is the vertex f(x)= 5x^2+20x-16
f(x) = 5x² + 20x - 16y = 5(x² + 4x) - 16y + 16 = 5(x² + 4x + __)perfect square:x² ⇒ x x4x ⇒ 22x2² = 4y + 16 + 4 = 5(x² + 4x + 4)y + 20 = 5(x+2)²(x+2)² ⇒ (x+2)(x+2) = x(x+2) + 2(x+2) = x² + 2x + 2x + 4 = x² + 4x + 4y = 5(x+2)² - 20