Math help?

2016-11-21 4:01 pm

Write the correct factorization for 81x2 - 4 = 0. Then find the solution(s).

回答 (5)

2016-11-21 4:48 pm

( 9 x - 2 ) ( 9 x + 2 ) = 0
x = 2/9 , x = - 2/9

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2016-11-21 4:41 pm

81x^2 - 4 = 0
(9x)^2 - (2)^2 = 0
(9x + 2)(9x - 2) = 0
Solutions:
x = -2/9
x = 2/9

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2016-11-21 4:27 pm

81x^2 - 4 = 0
(9x)^2 -2^2 = 0
(9x+2)(9x-2) = 0
9x+2 = 0
9x=-2
x=-2/9 -----(1)
9x-2=0
9x=2
x=2/9 -----(2)

(1) & (2) are solutions

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2016-11-21 4:06 pm

If the 2 is an exponent, it needs to written as ² or ^2.

81x² - 4 = 0
(9x+2)(9x-2) = 0
x = ±2/9

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2016-11-21 4:04 pm

The difference of squares is factored as
.. (9x -2)(9x +2) = 0
.. x = ±2/9

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