Question

Jika X1 dan X2 adalah akar-akar dari persamaan kuadrat -3x^ + 9x+21=0
maka nilai dari (x1=x2)-2(x1.x2)

Answer 1

-3x² + 9x + 21 = 0
a = -3, b = 9, c = 21

= = = 3
  = = = -7

Answer 2

-3x² + 9x+21=0
a = -3 b =9 c = 21
X1. X2 = c/a = 21/-3 = -7

X1=X2 = -b/2a = -9/2(3) = -9/6 = 3/2

nilai (X1=X2)-2(X1.X2)
(3/2) -2 (-7)
-3 x -7 = 21

mudah mudahan bener