jika x1 dan x2 akar akar dari persamaan x²+4x-2=0,nilai x1²+x2² adalah

x² + 4x - 2 = 0
a = 1
b = 4
c = -2

x1 + x2 = -b/a
x1 . x2 = c/a

x1² + x2² = (x1 + x2)² - 2x1x2
x1² + x2² = (-b/a)² - 2(c/a)
x1² + x2² = (-4/1)² - 2(-2/1)
x1² + x2² = 16 - 2(-2)
x1² + x2² = 16 + 4
x1² + x2² = 20

*harap koreksi