McGraw Hill Integrated II, 2012
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McGraw Hill Integrated II, 2012 View details
10. Roots and Zeros
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Exercise 64 Page 79

The formula to factor the difference of two squares is a^2-b^2=(a+b)(a-b).

B

Practice makes perfect
Look closely at the area of a rectangle 25a^4-16b^2. It can be expressed as the difference of two perfect squares.
25a^4-16b^2
25* a^(2*2)-16* b^2
25* (a^2)^2-16* b^2
5^2*(a^2)^2-4^2* b^2
(5a^2)^2-(4b)^2
Recall the formula to factor a difference of squares. a^2- b^2 ⇔ ( a+ b)( a- b) We can apply this formula to our expression. ( 5a^2)^2-( 4b)^2 ⇕ ( 5a^2+ 4b)( 5a^2- 4b) Therefore, (5a^2+4b) units and (5a^2-4b) units can represent the length and width of the rectangle. This corresponds to the answer B.

Checking Our Answer

Check your answer âś“
We can apply the Distributive Property and compare the result with the given expression.
(5a^2+4b)(5a^2-4b)
5a^2(5a^2-4b)+4b(5a^2-4b)
25a^4-20a^2b+4b(5a^2-4b)
25a^4-20a^2b+20a^2b-16b^2
25a^4-16b^2
After applying the Distributive Property and simplifying, the result is the same as the given rectangle area. Therefore, we can be sure our solution is correct!