Q. Rewrite the expression as a product of four linear factors:(x2+7x)2+4(x2+7x)−96Answer:
Recognize Structure: Recognize the structure of the given expression The given expression resembles a quadratic in form, where the variable part (x2+7x) is squared and then linearly combined with a constant. This suggests that we might be able to factor it by treating (x2+7x) as a single variable.
Substitute Single Variable: Substitute a single variable for the repeated expressionLet y=x2+7x. The expression becomes y2+4y−96.
Factor Quadratic Expression: Factor the quadratic expression in terms of y We need to find two numbers that multiply to −96 and add to 4. These numbers are 12 and −8. So, y2+4y−96=(y+12)(y−8).
Substitute Back: Substitute back x2+7x for yReplace y with x2+7x in the factored form to get:(x2+7x+12)(x2+7x−8).
Factor Each Quadratic: Factor each quadratic separatelyWe now have two quadratics to factor. We need to find two numbers that multiply to 12 and add to 7 for the first quadratic, and two numbers that multiply to −8 and add to 7 for the second quadratic.For the first quadratic: The numbers are 3 and 4.So, x2+7x+12=(x+3)(x+4).For the second quadratic: The numbers are 1 and −8.So, x2+7x−8=(x+8)(x−1).
Combine Factors: Combine the factors to express the original expression as a product of four linear factorsThe original expression is now factored as:(x+3)(x+4)(x+8)(x−1).