Q. Factor the expression completely.x4−3x2−4Answer:
Recognize Structure: Recognize the structure of the expression.The given expression is a quadratic in form, but with a variable to the fourth power:x4−3x2−4We can treat x2 as a single variable, let's say u, to make it look like a standard quadratic equation:u2−3u−4
Factor Quadratic Expression: Factor the quadratic expression.Now, we factor u2−3u−4 as if it were a regular quadratic equation. We are looking for two numbers that multiply to −4 and add up to −3. These numbers are −4 and +1.So we have:(u−4)(u+1)
Substitute Back: Substitute back x2 for u. Now we replace u with x2 to get back to the original variable: (x2−4)(x2+1)
Factor Further: Factor further if possible.The term (x2+1) is not factorable over the real numbers because it has no real roots. However, (x2−4) is a difference of squares and can be factored further:(x2−4)=(x−2)(x+2)
Write Completely Factored Expression: Write the completely factored expression. Combining the factors from the previous steps, we get the completely factored form of the original expression: x - \(2)(x + 2)(x^2 + 1)\
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