# solve by factoring/give an example please

• Feb 27th 2008, 12:14 PM
dblued
solve by factoring/give an example please
w2-169=0

36a2= 169

15t2-11t-12= 0
• Feb 27th 2008, 12:48 PM
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?.

$(w)^{2}-(13)^{2}$. Now, can you factor using the proper form?. (x+y)(x-y).
• Feb 28th 2008, 04:55 PM
quarks
$36a^2=169$

Take the square root of both sides.

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

$6a=13$

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

For the other one, you can factor it.

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

And from there, it's easy to solve.
• Feb 28th 2008, 05:26 PM
topsquark
Quote:

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

Take the square root of both sides.

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

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

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

-Dan
• Feb 28th 2008, 05:29 PM
quarks
Yeah. Thanks. =) My mistake.