20x²+13x–72 full answer for this question
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Correct Question : Factorise 20x² + 13x - 72
SOLUTION :
20x² + 13x - 72
As, 20 is coefficient of 20x², so multiply 20 with 72
20x² + 13x - 72
Split the middle terms
20x² - 32x + 45x - 72
4x(5x - 8) + 9(5x - 8)
(4x + 9) (5x - 8)
Zeroes are :
4x + 9 = 0
4x = -9
x = -9/4
5x - 8 = 0
5x = 8
x = 8/5
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