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15 votes
15 votes
Factor completely 25-64x^2

User Pinser
by
3.0k points

2 Answers

9 votes
9 votes

Answer:

(5+8) (5-8)

Explanation:

They are both perfect squares.

User Early
by
3.0k points
14 votes
14 votes

Answer:

(5+8x)(5-8x)

Explanation:

This is a 'difference of two squares" Difference means subtraction and 25 is a perfect square and 64x^2 is a perfect square.

If you know how to factor quadratic trinomials like

ax^2 + bx + c, you can do the same thing here, using:

64x^2 +0x + 25

BUT, there's a shortcut. It is a pattern that you memorize. Since 25 is 5^2, put 5 first in the parenthesis. And since 64x^2 is 8x squared, put 8x second in the parenthesis like this:

(5 8x)

Make two of them:

(5 8x)(5 8x)

Make one a plus and one a minus.

(5 + 8x)(5 - 8x)

Done!

Well, if the directions say "factor" then you are done. If the directions say "solve" then put each piece equal to zero and solve for x.

Hope this helps!

User Horse SMith
by
2.9k points
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