the general rule is that : a^2 - b^2 = (a+b)(a-b)
So, 9y^2 - 1 = (3y+1)(3y-1) = 0
3y = -1 or 3y = 1
y = +/- 1/3
2007-06-02 03:09:29
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answer #1
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answered by English Learner 2
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There is a difference between FACTORING and SOLVING an equation. You can SOLVE the equation, as follows:
9y^2 - 1 = 0
9y^2 = 1
y^2 = 1/9
y = +1/3 or -1/3
FACTORING means determining two or more expressions that when multiplied together result in the term on the left side of the equation. The equation can be FACTORED, as follows:
9y^2 -1 = 0
(3y +1) * (3y - 1) = 0
=>
3y + 1 = 0
or
3y - 1 = 0
3y + 1 = 0
3y = -1
y = -1/3
3y - 1 = 0
3y = 1
y = 1/3
2007-06-02 10:17:59
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answer #2
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answered by wow_bill 7
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This is "The difference of 2 perfect squares."
9y^2 is 3y squared; 1 is 1x1 or 1 squared
(3y + 1)( 3y - 1)
http://www.coolmath.com
2007-06-02 10:14:00
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answer #3
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answered by Anonymous
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Here we are asked to factor out 9y^2-1=0.
The 9 can be written as 3^2, then 9y^2-1= 0 becomes
3^2y^2 -1^2 =0
we know that x^2y^2 = (xy)^2
(3y)^2 -1^2 = 0.
By the formula, we can write it as,
(3y+1)(3y-1) =0
Implies that (3y+1) = 0 or (3y-1) =0
Finally we get y= -1/3 or y = 1/3.
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2007-06-05 23:42:40
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answer #4
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answered by Anonymous
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This is a difference of squares, so it factors as
(3y-1)*(3y+1) = 0 and
y = ± 1/3
Doug
2007-06-02 10:07:08
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answer #5
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answered by doug_donaghue 7
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9.y² = 1
y² = 1 / 9
y = ± (1/3)
or
(3y - 1).(3y + 1) = 0
y = 1/3 , y = - 1/3 (as above)
2007-06-02 14:26:54
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answer #6
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answered by Como 7
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9y^2 = 1
y^2 = 1/9
y= (radical) 1/9
2007-06-02 10:11:19
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answer #7
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answered by k i w i ♥182 7
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