I got this question to factorise: 4a squared - 9b squared. My friend says that it is the difference of two squares however there is not common factor? Can you help me solve this?
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You can use the identity A² - B² ≡ (A + B)(A - B)
4a² - 9b² = (2a)² - (3b)²
. . . . . . .= (2a + 3b)(2a - 3b)
4a² - 9b² = (2a)² - (3b)²
. . . . . . .= (2a + 3b)(2a - 3b)
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what you do is square root the coefficient in front of and in front of b. and then put them in an equation like this (2a-3b)(2a+3b)
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4a² - 9b² = (2a - 3b)(2a + 3b)
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(2a - 3b)(2a + 3b)
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(2a-3b) ( 2a + 3b)