(x - 3)^2 = 25?

2008-07-21 3:43 pm
A. x = ±5
B. x = ±√5
C. x = ±3
D. x = 8 and x = -2

回答 (11)

2008-07-21 3:52 pm
✔ 最佳答案
(x - 3)² = 25
x² - 6x +9 = 25
x² - 6x -16 = 0
(x -8)(x + 2) = 0

x = (8, -2)
2008-07-21 10:52 pm
(x-3)(x-3)=x^2-6x+9
x^2-6x+9-25=0
x^2-6x-16

D. x = 8 and x = -2
2008-07-21 10:50 pm
(x - 3)^2 = 25

Find the square root of both sides

x - 3 = +/-5

x = +/-5 + 3

x = + 5 + 3 = 8

x = -5 + 3 = -2

x = 8 and -2

Answer Letter D
2008-07-21 10:50 pm
D I verified it twice on paper
2008-07-21 10:50 pm
D. x = 8 and x = -2
2008-07-21 10:49 pm
The answer is D
2008-07-22 2:33 am
x - 3 = ± 5
x = 8 , x = - 2
OPTION D
2008-07-21 11:35 pm
(x – 3)² = 25
(x – 3) = √25 = ± 5
x – 3 = 5 or x – 3 = – 5
x = 8 or x = – 2 ----------- option D
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2008-07-21 11:07 pm
(x-3)^2=25
x^2-6x+9=25
x^2-6x+9-25=0
x^2-6x-16=0
(x-8)(x+2)=0
x-8=0
x=8,
x+2=0
x=-2
therefore X=8 and x=-2.so its letter D.
2008-07-21 10:57 pm
(x - 3)^2 = 25
x - 3 = ±√25
x - 3 = ±5

x - 3 = 5
x = 5 + 3
x = 8

x - 3 = -5
x = -5 + 3
x = -2

∴ x = -2 , 8
(answer D)


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