SAT Math : How to find the square of difference

Study concepts, example questions & explanations for SAT Math

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Example Questions

Example Question #1 : Squaring / Square Roots / Radicals

Simplify: \(\displaystyle (3x-4)^2\)

Possible Answers:

\(\displaystyle 9x^2-16\)

\(\displaystyle 9x^2+24x+16\)

\(\displaystyle 9x^2+16\)

\(\displaystyle 9x^2-24x+16\)

\(\displaystyle 9x^2-24x-16\)

Correct answer:

\(\displaystyle 9x^2-24x+16\)

Explanation:

If you don't already have the pattern memorized, use FOIL. It's best to write out the parentheses twice (as below) to avoid mistakes:

\(\displaystyle (3x-4)^2=(3x-4)(3x-4)\)

\(\displaystyle =9x^2-12x-12x+16\)

\(\displaystyle =9x^2-24x+16\)

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