persamaan kuadrat 4 x² + p = -1 mempunyai akar x₁ dan x₂ jika x₁ = 1/2 maka p(x² + x²₂ ) = ...?

4x² + px + 1 = 0
x1x2 = 1/4
(1/2)x2 = 1/4
x2 = 1/2

x1 + x2 = 1/2 + 1/2 = 1/4
-p/4 = 1/4
p = -1

p(x1² + x2²)
= p ((x1 + x2)² - 2x1x2)
= (-1)((1/16 - 8/16))
= 7/16