SOLUTION: How do I find the product of (5r+4)(5r-4)

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Question 757878: How do I find the product of (5r+4)(5r-4)
Found 2 solutions by lenny460, tommyt3rd:
Answer by lenny460(1073) About Me  (Show Source):
You can put this solution on YOUR website!
How do I find the product of (5r+4)(5r-4)
(5r + 4)(5r - 4)
5r * 5r = 25r^2
5r * -4 = -20r
4 * 5r = 20r
4 * -4 = -16
Therefore:
25r^2 - 20r + 20r - 16
Combine like terms:
-20r + 20r = 0
25r^2 - 16


Answer:
25r^2 - 16









Lennox Obuong
Algebra Tutor
Nairobi, Kenya
Email: lennoxobuong@yahoo.com

Answer by tommyt3rd(5050) About Me  (Show Source):
You can put this solution on YOUR website!
Difference of squares:


%285r%2B4%29%285r-4%29=%285r%29%5E2-%284%29%5E2=25r%5E2-16


:)