SOLUTION: 9x4=25x2 -16 the x is to the 4th power, and the x is 2 the 2nd power , didn't know hot to type these right on the computer/ Its a "substitution problem so i replaced x squared

Algebra ->  Radicals -> SOLUTION: 9x4=25x2 -16 the x is to the 4th power, and the x is 2 the 2nd power , didn't know hot to type these right on the computer/ Its a "substitution problem so i replaced x squared       Log On


   

Question 15681: 9x4=25x2 -16
the x is to the 4th power, and the x is 2 the 2nd power , didn't know hot to type these right on the computer/ Its a "substitution problem so i replaced x squared with a t so i get 9t2 (t squared ) -25t +16. . i cannot figure out how to factor this.
Answer by rapaljer(4671) About Me  (Show Source):
You can put this solution on YOUR website!
First of all, you can use the subsitution, but don't LOSE the equation. What you probably mean is this:
9t%5E2+-25t+%2B+16+=+0

This factors into:
%289t-16%29%2A%28t-1%29+=+0+

Notice that the outer times outer term is -9t, and the inner times inner is -16t, and this adds up to -25t, which is the middle term.
%289t-16%29%2A%28t-1%29+=+0+
9t+-+16=+0
9t+=+16
t=+16%2F9

Also, t=1.

Now you have to go back and solve for x, where you made the substitution x%5E2+=+t
x%5E2+=+t
x%5E2+=+16%2F9
x=+4%2F3 or x=+-4%2F3

x%5E2+=+t
x%5E2+=+1
x=+1 or x=+-1

R^2 at SCC