SOLUTION: I am taking and online algebra II class and I do not understand how to solve this equation (y^2-9)(9y^2-9y+8) the instructions saty multiply. Would I use the foil method? This is

Algebra ->  Systems-of-equations -> SOLUTION: I am taking and online algebra II class and I do not understand how to solve this equation (y^2-9)(9y^2-9y+8) the instructions saty multiply. Would I use the foil method? This is      Log On


   

Question 325769: I am taking and online algebra II class and I do not understand how to solve this equation (y^2-9)(9y^2-9y+8) the instructions saty multiply. Would I use the foil method?
This is what I came up with
(y^2-9)(9y^2-9y+8)
Y^2*9y^2=9y^4
y^2*-9y=-9y^3
y^2*8=8y^2
-9*9y^2=-81y^2
-9*-9y=81y^2
-9*8=72
9y^4-9y^3+8y-81y^2+81y^2-72
9y^4-9y^3+8y-y^2-72
Is this correct?
Found 2 solutions by jim_thompson5910, nyc_function:
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
%28y%5E2-9%29%289y%5E2-9y%2B8%29 Start with the given expression.


y%5E2%289y%5E2-9y%2B8%29-9%289y%5E2-9y%2B8%29 Expand.


Distribute.


9y%5E4-9y%5E3%2B8y%5E2-81y%5E2%2B81y-72 Multiply.


9y%5E4-9y%5E3-73y%5E2%2B81y-72 Now combine like terms.


So %28y%5E2-9%29%289y%5E2-9y%2B8%29 expands to 9y%5E4-9y%5E3-73y%5E2%2B81y-72.


In other words, %28y%5E2-9%29%289y%5E2-9y%2B8%29=9y%5E4-9y%5E3-73y%5E2%2B81y-72.

Answer by nyc_function(2741) About Me  (Show Source):
You can put this solution on YOUR website!
First of all, there is no equation here. You cannot have an equation without the EQUAL sign. Secondly, you must multiply every member of (y^2-9) by every member of(9y^2-9y+8). Afterwards, simplify by combining like terms. Thirdly, the first-two terms are correct. The last term is correct but terms 3 and 4 in your answer are not right.
Let's do it term by term.
y^2 * 9y^2 = 9y^4
y^2 * -9y = -9y^3
y^2 * 8 = 8y^2
I have completed the multiplication for the y^2 term.
-9 * 9y^2 = -81y^2
-9 * -9y = 81y
-9 * 8 = -72
I have completed the multiplication for the -9 term.
We now have the following:
9y^4 - 9y^3 + 8y^2 - 81y^2 + 81y - 72 =
We now combine like terms and that's it.
9y^4 - 9y^3 -73y^2 + 81y - 72
Did you follow?