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(2x + 5) 2 - (2x - 5) 2 = [(2x) 2 + 2(2x)(5) + (5) 2 ] - [(2x) 2 - 2(2x)(5) + (5) 2 ] = [4x 2 + 20x + 25] - [4x 2 - 20x + 25] = 4x 2 + 20x + 25 - 4x 2 + 20x - 25 = (4x 2 - 4x 2 ) + (20x + 20x) + (25 - 25) = 0 + 40x + 0 = 40x

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Algebraic Expressions and Identities

Short Answer Type

111.

Find the following squares by using the identities.

(xy + 3z)²

118 Views

112.

Find the following squares by using the identities.

(6x² - 5y)²

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113.

Find the following squares by using the identities.

$space space space space space space space space space space space open parentheses 2 over 3 straight m space plus space 3 over 2 straight n close parentheses squared$

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114.

Find the following squares by using the identities.

(0.4p - 0.5q)²

335 Views

115.

Find the following squares by using the identities.

(2xy + 5y)²

84 Views

116.

Simplify:

(a²- b²)²

174 Views

117.
Simplify:

(2x + 5)²- (2x - 5)²

(2x + 5)²- (2x - 5)²= [(2x)²+ 2(2x)(5) + (5)²] - [(2x)²- 2(2x)(5) + (5)²]
                            = [4x²+ 20x + 25] - [4x²- 20x + 25]
                            = 4x²+ 20x + 25 - 4x²+ 20x - 25
                            = (4x²- 4x²) + (20x + 20x) + (25 - 25)
                            = 0 + 40x + 0
                            = 40x