Please show me how to factor this polynomial 25y^2 -64, thanks
2007-05-26 03:59:34 · 3 answers · asked by mamacitasue 1 in Science & Mathematics ➔ Mathematics
You need to recognize that each part of that expression is a perfect square. Therefore, you would use the factoring method called "Difference of two swuares."
You first need to take the sqrt of both parts. So ...
sqrt (25y²) = 5y .... and .... sqrt (64) = 8
Now, using this method, you know that you are going to take the two sqrt's and subtract them then add them ... so ....
(5y + 8)(5y - 8) .... that is completely factored!!
You know this is true because if you multiply those two binomails using the FOIL method (or distribution property depending on how your teacher explains it to you) you get the original expression ...
25y² - 40y + 40y - 64 ... 25y² - 64
Good luck with the rest of your homework!
2007-05-26 04:05:44 · answer #1 · answered by TripleFull 3 · 0⤊ 0⤋
First of all require two numbers that multoply to give 25y²
These are 5y and 5y:-
(5y-----).(5y-----)
Now require two numbers that multiply to give - 64
These could be - 8 and 8 so try these:-
(5y - 8).(5y + 8) is answer.
Check
5y.(5y + 8) - 8.(5y + 8)
25y² + 40y - 40y - 64
25y² - 64 (as required)
2007-05-26 16:27:03 · answer #2 · answered by Como 7 · 0⤊ 0⤋
It's just a difference of squares, so it would factor to be (5y+8)(5y-8).
2007-05-26 11:03:05 · answer #3 · answered by Y^2 2 · 3⤊ 1⤋