Q. Rewrite the expression as a product of four linear factors:(5x2−9x)2−16(5x2−9x)+28Answer:
Identify Expression: Identify the given expression and recognize that it resembles a quadratic in form, where the variable part is (5x2−9x).The expression is: (5x2−9x)2−16(5x2−9x)+28
Set Substitution: Let's set a substitution to simplify the expression. Let u=5x2−9x. The expression then becomes:u2−16u+28This is a quadratic equation in terms of u.
Factor Quadratic Equation: Factor the quadratic equation u2−16u+28. We are looking for two numbers that multiply to 28 and add up to −16. These numbers are −14 and −2. So, the factored form is (u−14)(u−2).
Substitute Back: Now, substitute back 5x2−9x for u in the factored expression to get: (5x2−9x−14)(5x2−9x−2)
Factor First Quadratic: Each quadratic factor can be further factored into two linear factors. We will start with the first quadratic factor 5x2−9x−14. We need to find two numbers that multiply to (5×−14)=−70 and add up to −9. These numbers are −14 and 5. So, the factored form is (5x+5)(x−14).
Factor Second Quadratic: Now, factor the second quadratic factor 5x2−9x−2. We need to find two numbers that multiply to (5×−2)=−10 and add up to −9. These numbers are −10 and 1. So, the factored form is (5x+1)(x−2).
Combine Linear Factors: Combine the linear factors from both quadratic factors to express the original expression as a product of four linear factors:(5x+5)(x−14)(5x+1)(x−2)
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