Homework Help: 9th grade Algebra

Posted by Reed on Wednesday, August 22, 2012 at 9:25pm.

Did I get the right answer for this? Evaluate the expression
3x squared - 5x when x= -2 My Answer is 46. I got this by doing 3 times -2 and squaring that and then multiplying 5 times -2 and subtracting that ( negative 10 ) from 36. Is this correct?

9th grade Algebra - Kirk, Wednesday, August 22, 2012 at 9:31pm
Im sorry but you did it wrong. Remember your order of operations. First do whats in parenthasis, so nothing then exponents. catch me first off is you will get this when you substitute in. 3(-2)^2-5*-2. so you square your -2 which gives you -4 so now you got 3*-4-5*-2. so now we do our multiplication and divsion. -12+10 and we get -2
9th grade Algebra - Reiny, Wednesday, August 22, 2012 at 10:46pm
3x^2 - 5x

when x=-2 we get
3(-2)^2 - 5(-2)
= 3(4) + 10
= 12 + 10
= 22

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