Solve for “x” by factoring: x squared-2x=63?
回答 (8)
2009-04-09 11:18 am
✔ 最佳答案
(x+7)(x-9)x=( -7, 9)
2009-04-09 11:19 am
x² - 2x = 63
x² - x = 63 + (- 1)²
x² - x = 63 + 1
(x - 1)² = 64
x - 1 = 8
Factors:
= x - 1 - 8, = x - 9
= x - 1 + 8, = x + 7
Values of x:
x - 9 = 0, x = 9
x + 7 = 0, x = - 7
Answer: x = 9, - 7
Proof (x = 9):
9² - 2(9) = 63
81 - 18 = 63
63 = 63
Proof (x - 7):
(- 7)² - 2(- 7) = 63
49 + 14 = 63
63 = 63
x² - x = 63 + (- 1)²
x² - x = 63 + 1
(x - 1)² = 64
x - 1 = 8
Factors:
= x - 1 - 8, = x - 9
= x - 1 + 8, = x + 7
Values of x:
x - 9 = 0, x = 9
x + 7 = 0, x = - 7
Answer: x = 9, - 7
Proof (x = 9):
9² - 2(9) = 63
81 - 18 = 63
63 = 63
Proof (x - 7):
(- 7)² - 2(- 7) = 63
49 + 14 = 63
63 = 63
2016-12-03 9:15 pm
7 is right. once you plug it in for x, you get 7^2 + 14 = 40 9 + 14 = sixty 3. besides the undeniable fact that, there are 2 suggestions. the different is -9. that is with the aid of fact once you sq. a destructive type, you get a favorable type. so which you have (-9)^2 + 2(-9) = 80 one - 18 = sixty 3.
2009-04-09 12:46 pm
x^2 - 2x = 63
x^2 - 2x - 63 = 0
x^2 + 7x - 9x - 63 = 0
(x^2 + 7x) - (9x + 63) = 0
x(x + 7) - 9(x + 7) = 0
(x + 7)(x - 9) = 0
x + 7 = 0
x = -7
x - 9 = 0
x = 9
∴ x = -7 , 9
x^2 - 2x - 63 = 0
x^2 + 7x - 9x - 63 = 0
(x^2 + 7x) - (9x + 63) = 0
x(x + 7) - 9(x + 7) = 0
(x + 7)(x - 9) = 0
x + 7 = 0
x = -7
x - 9 = 0
x = 9
∴ x = -7 , 9
2009-04-09 11:42 am
x^2 - 2x = 63
-63 -63
x^2 - 2x - 63 = 0
(x-9) (x+7)
x=9
x=-7
-63 -63
x^2 - 2x - 63 = 0
(x-9) (x+7)
x=9
x=-7
2009-04-09 11:22 am
x squared-2x=63
x squared-2x -63=0
(x-9)(x+7)=0
x= 9 or -7
x squared-2x -63=0
(x-9)(x+7)=0
x= 9 or -7
2009-04-09 11:21 am
x² - 2x = 63
x² - 2x - 63 = 0
(x + 7)(x - 9) = 0
x = -7, 9
Done
x² - 2x - 63 = 0
(x + 7)(x - 9) = 0
x = -7, 9
Done
2009-04-09 11:20 am
(x-9)(x+7)=0
x=9
x=-7
x=9
x=-7
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