What factorization can be used to reveal the zeros of f(x) = 12x²  11x + 15 ?
A.) f(x) = x(12x + 11) + 15 B.) f(x) = (4x + 3)(3x + 5) C.) f(x) = (4x + 3)(3x + 5) D.) f(x) = (4x + 3)(3x + 5)
f(x) = 12x²  11x + 15
= 1(12x² + 11x  15) {factored 1 out} = (12x² + 20x  9x  15) {factoring by grouping......split the middle term, 11x, into 20x and 9x} = [4x(3x + 5)  3(3x + 5)] {factored 4x out of first two terms and 3 out of last two terms} = (3x + 5)(4x  3) {factored out the common factor, (3x + 5)} Looking at the answer choices, the only one that matches is: B.) f(x) = (4x + 3)(3x + 5) {distributed negative sign to (4x  3)} Ask Algebra House Comments are closed.

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