Question

Persamaan kuadrat x^2-2x-2=0 mempunyai akar a dan b. Nilai dari (1)/(a)+(1)/(b) adalah ....

A. -4
B. -2
C. -1
D. 1
E. 2

Answer 1

X^2 - 2x - 2 = 0
a = 1
b = -2
c = -2

a + b = -b/a
a + b = -(-2)/1
a + b = 2

ab = c/a
ab = -2/1
ab = -2

1/a + 1/b
= (b + a)/ab
= (a + b)/ab
= 2/(-2)
= -1

Jawaban: C