Need some College Algebra help on trinominals?

Question

I have two project problems I definitely do not understand how to do. I had a classmate try and help me with the second math problem. But I still do not understand what to do. So if anyone could help me out that would be greatly appreciated.

Simplify and evaluate:
1. (4^2x^3y^-2z^-3/x^-5y^8z^-9)^2

Multipy:
2. (x^4 – 4x^2 – 5)(x^2 – x + 2)

My classmate tried to help me with the second problem and said that it is like a FOIL problem. But I don't see how or where. Cause when I go to multiply this problem out I got x^6 +x^3 +7, but my classmate said she got a longer answer. So if anyone could make sense out of these two problems for me that would be great. Thank you.

bananarichwaffle · Accepted Answer

is this really college algebra?

>.< i'm taught in a different education system... but this looks... too trivial to be college algebra. 

anyway, the first question:
hint: 1/ x^-5   = x^5
hint2: x^5 multiply by x^-7 = x ^(5-7) = x^(-2) [just a summation of power]
hint3: do the parts in () first. 
so what you have to do first is:
1) make the 2 x in the qn to become 1 x. 
2) repeat for y
3) repeat for z.
4) leave the constant aka 16 alone.
5) then work outside of the bracket. 

this qn is not difficult. relax. :) you can do it.

regarding question 2, your answer is wrong.
just by glancing at the equation, you are missing out several terms like x^5, x, x^2.
hint3: (a + b +c)(d+e+f)  = a(d+e+f) + b(d+e+f) + c(d+e+f)
slowly work it out. remember hint 2. :)

your ans should look sth like this:
Ax^6 + Bx^5 + Cx^4 + Dx^3 + Ex^2 + Fx^1 + G, 
where A,B,C,D,E,F,G is constant and is real (taking any value from negative infinity to positive infinity,) 


comeee onnn. you can DO IT!

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Need some College Algebra help on trinominals?

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