factorise 9x^4 -x^2 -12x-36
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Answer: dude here ur answer...
Step-by-step explanation:
Because you have 9x^2, and 9 = 3^2, you know that both factors are going to contain 3x (or -3x).
So it's (3x+a)(3x+b).
a*b = -6 so a = -6/b
3a + 3b = 4
substitute for a
3(-6/b) + 3b = 4
-18/b + 3b = 4
multiply both sides by b
-18 + 3b^2 = 4b
rearrange this
3b^2 - 4b - 18 = 0
solve this for b and you will have your answer
Hope it's help
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