Problem is 27x^2-117x-90 So should I take the GCF of 9 out first? 9(3x^2-13x-10) Or do I look at the problem before that and see if it is a perfect-square? Thanks
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when I work it out i get 9(3x+2)(x-5)
Originally Posted by bashemgud Problem is 27x^2-117x-90 The $\displaystyle {\bf\color{red}-}90$ tells you it is not a square trinominal.
Originally Posted by Plato The $\displaystyle {\bf\color{red}-}90$ tells you it is not a square trinominal. can you tell me why?
Originally Posted by moonwoo can you tell me why? The constant term in a perfect square is always positive. Expand $\displaystyle (a+b)^2$ and note the sign of b^2
Originally Posted by bashemgud when I work it out i get 9(3x+2)(x-5) This is correct. Clearly this is not a perfect square...
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