Question

Factor the expression completely.
x^4-15x^2+54

Answer 1

x^2(x^2 - 15) + 9(x-6)(x+1)

Explanation:

To factor the expression x^4 - 15x^2 + 54 completely, we need to find the common factors in each term. In this case, we can see that the terms x^4 and -15x^2 share a common factor of x^2. To factor this out, we can use the difference of squares factorization:

x^4 - 15x^2 + 54 = x^4 - 15x^2 + (9x^2 - 9x^2) + 54

= x^2(x^2 - 15) + 9(x^2 - 6)

= x^2(x^2 - 15) + 9(x-6)(x+1)

Since x^2-15 can't be factored further. The expression is fully factored.

We can check this by multiplying it back and it should be the same as original expression.