Q. Factor the expression completely.x4−4x2−12Answer:
Recognize Structure: Recognize the structure of the expression.The expression x4−4x2−12 resembles a quadratic in form, where x2 is the variable instead of x. This suggests we can factor it similarly to how we would factor a quadratic equation.
Factor as Quadratic: Factor the expression as if it were a quadratic.We are looking for two numbers that multiply to −12 and add up to −4 (the coefficient of the middle term). These numbers are −6 and +2.So, we can write the expression as (x2−6)(x2+2).
Check for Further Factoring: Check for further factoring possibilities.The term (x2+2) cannot be factored further over the real numbers because it does not have real roots. However, the term (x2−6) is a difference of squares and can be factored further.
Factor Difference of Squares: Factor the difference of squares.The expression x2−6 can be written as (x−6)(x+6) because (x−6)(x+6)=x2−(6)2=x2−6.
Combine Factors: Combine all factors to write the final factored expression.The completely factored form of the expression is (x−6)(x+6)(x2+2).
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