Question

3) As raizes da equação x2 - 9x + 18 = 0 são:
(A) X=2eX = 7
(B) X = 3 x = 6
(C) X = 4X-5
(D) X = 1eX = 8​

Answer 1

ANSWER

b) X = 3 X = 6

EXPLICATION

∆= b2 - 4 (a.c)

∆= -9(2) - 4 (1.18)

∆= 81 - 4 (18)

∆= 81 - 72

∆= 9

X= -b +ou- √∆

2(a)

X= -(-9) +ou- √9

2(1)

X= 9 +ou- 3

2

X= 9 - 3 X= 9 + 3

2 2

X= 6÷2 = 3 X= 12÷2 = 6