Question

Diketahui f(x2 + bx + 2) = 2x + 3 dan f(0) = – 1, maka nilai b adalah … .

Answer 1

F⁻¹(2x+3) = x² + bx + 2
f⁻¹(-1) = 0
2x + 3  = -1
2x = -4
x = -2

f⁻¹(-1) = 0
(-2)²+b(-2) +2 = 0
4 - 2b +2 = 0
- 2b = -6
b =  3
...

Answer 2

F(x² + bx + 2) = 2x + 3
f(0) = -1


2x + 3 = -1
2x = -1 - 3
2x = -4
x = -4/2 = -2


f((-2)² - 2b + 2) = 2(-2) + 3
f(4 - 2b + 2) = -4 + 3
f(6 - 2b) = -1


6 - 2b = 0
-2b = 0 - 6
-2b = -6
b = -6/(-2)
b = 3


maka nilai b adalah 3