SOLUTION: How do I factor this? {{{ x^4 -13x^2 + 36}}} The answer is (x -2) (x + 2) (x -3) (x + 3) This seems to be a case of difference of squares, but I don't know how to factor i

Algebra ->  Expressions-with-variables -> SOLUTION: How do I factor this? {{{ x^4 -13x^2 + 36}}} The answer is (x -2) (x + 2) (x -3) (x + 3) This seems to be a case of difference of squares, but I don't know how to factor i      Log On


   

Question 903854: How do I factor this?
+x%5E4+-13x%5E2+%2B+36
The answer is (x -2) (x + 2) (x -3) (x + 3)
This seems to be a case of difference of squares, but I don't know how to factor it with a 4th degree.
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
x%5E4-13x%5E2%2B36

x%5E4-4x%5E2-9x%5E2%2B36 -4 and -9 both add to -13 and multiply to 36

%28x%5E4-4x%5E2%29%2B%28-9x%5E2%2B36%29

x%5E2%28x%5E2-4%29%2B%28-9x%5E2%2B36%29

x%5E2%28x%5E2-4%29-9%28x%5E2-4%29

%28x%5E2-9%29%28x%5E2-4%29

%28x-3%29%28x%2B3%29%28x%5E2-4%29 Difference of squares rule

%28x-3%29%28x%2B3%29%28x-2%29%28x%2B2%29 Difference of squares rule

Note: the order of the factors doesn't matter.