Q. Rewrite the expression as a product of four linear factors:(7x2+15x)2−16(7x2+15x)−36Answer:
Identify Expression Form: Identify the given expression and recognize that it resembles a quadratic in form, where the variable part is (7x2+15x). The expression is: (7x2+15x)2−16(7x2+15x)−36 Let's denote u=7x2+15x, so the expression becomes: u2−16u−36
Denote Variable: Now, we need to factor the quadratic expression u2−16u−36. We are looking for two numbers that multiply to −36 and add up to −16. These numbers are −18 and +2. So we can write the quadratic as: (u−18)(u+2)
Factor Quadratic Expression: Substitute back 7x2+15x for u in the factored form to get: (7x2+15x−18)(7x2+15x+2)
Substitute Variable Back: Now, we need to factor each quadratic expression further. We start with 7x2+15x−18. We look for two numbers that multiply to 7×−18=−126 and add up to 15. These numbers are 21 and −6. So we can write the quadratic as: (7x−6)(x+3)
Factor First Quadratic: Next, we factor 7x2+15x+2. We look for two numbers that multiply to 7×2=14 and add up to 15. These numbers are 14 and 1. So we can write the quadratic as: (7x+1)(x+2)
Factor Second Quadratic: Combine all the linear factors to express the original expression as a product of four linear factors:(7x−6)(x+3)(7x+1)(x+2)
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