Question

Titik balik maksimum dari fungsi kuadrat f(x) = (5 + 2x) (1 - x) adalah
A. (2/3 , 8 1/6)
B. (-3/4 , 6 1/8)
C. (3/4 , 6 1/8)
D. (-3/4 , -6 1/8)
E. (-2/3 , 8 1/6)

Answer 1

F(x) = (5 + 2x)(1 - x)
     = 5 - 5x + 2x - 2x²
     = - 2x² - 3x + 5
titik balik:
x = - b/2a = - (-3)/- 4
               = 3/4
f(3/4) = - 2(3/4)² - 3(3/4) + 5 = 49/8 = 6 1/8
maka koordinat titik baliknya:
(3/4 , 6 1/8)
Jawaban: C

Answer 2

Fx=5-2x²+2x-5x=-2x²-3x+5

x=-b/2a
x=-(-3)/2{(-2)
x=-¾

y=fx=-2(-¾)²-3(-¾)+5
y=-9/