solve by factoring/give an example please

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• Feb 27th 2008, 11:14 AM
dblued
solve by factoring/give an example please
w2-169=0

36a2= 169

15t2-11t-12= 0
• Feb 27th 2008, 11:48 AM
galactus
Please use the ^ sign for powers. As you have it written, the first one means

w times 2.

But anyway, for the first one. Notice the difference of two squares?.

$\displaystyle (w)^{2}-(13)^{2}$. Now, can you factor using the proper form?. (x+y)(x-y).
• Feb 28th 2008, 03:55 PM
quarks
$\displaystyle 36a^2=169$

Take the square root of both sides.

$\displaystyle \sqrt{36a^2}\ = \sqrt 169$

$\displaystyle 6a=13$

$\displaystyle a= \frac{13}{6}$

For the other one, you can factor it.

$\displaystyle 15t^2-11t-12 = (3t-4)(5t+3)$

And from there, it's easy to solve.
• Feb 28th 2008, 04:26 PM
topsquark
Quote:

Originally Posted by quarks
$\displaystyle 36a^2=169$

Take the square root of both sides.

$\displaystyle \sqrt{36a^2}\ = \sqrt 169$

So far, so good. But
$\displaystyle \sqrt{36a^2} = \sqrt{169}$
implies
$\displaystyle 6a = \pm 13$

$\displaystyle a = \pm \frac{13}{6}$

-Dan
• Feb 28th 2008, 04:29 PM
quarks
Yeah. Thanks. =) My mistake.