Use suitable identity to find the product: (3x + 4)(3x - 5) - Vidyadip

Question

Use suitable identity to find the product: (3x + 4)(3x - 5)

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Answer

(3x + 4)(3x - 5)
= (3x + 4){3x + (-5)}
{Using identity (x + a)(x + b) = x²+ (a + b) x + ab}
= (3x)² + {4 + (-5)}(3x) + (4)(-5)
= 9x² - 3x - 20

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