Expand and simplify $(x + 2)(3x - 7)$.
A$3x^{2} + x - 14$
B$3x^{2} - x - 14$
C$3x^{2} + x + 14$
D$3x^{2} - 13x - 14$
Answer & Solution
Correct answer: B. $3x^{2} - x - 14$
Multiply each term of the first binomial by each term of the second:
$x(3x) + x(-7) + 2(3x) + 2(-7) = 3x^{2} - 7x + 6x - 14$.
Combine like terms: $-7x + 6x = -x$, so the result is $3x^{2} - x - 14$.
Trap A flips the sign of the middle term — easy to make if you forget that $-7x + 6x$ is $-x$, not $+x$.
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