Question

Read each question. Then fill in the correct answer on the answer document provided by your teacher or on a sheet of paper.

The expression$\left(3x^2+5x-12\right)-2\left(x^2+4x+9\right)$is equivalent to which of the following?

F$x^2-3x-30$

G$x^2+13x+6$

H$5x^2+x-18$

J$x^2+3x-21$

Short answer

The equivalent of the given expression is $x^2-3x-30$.

Step-by-step solution

Step 1. Given information.

An expression $\left(3x^2+5x-12\right)-2\left(x^2+4x+9\right)$.

Step 2. To find the simple form of expression.

Solve the given expression,

$\begin{array}{l}\left(3x^2+5x-12\right)-2\left(x^2+4x+9\right)\\ =3x^2+5x-12-2x^2-8x-18\\ =3x^2-2x^2+5x-8x-12-18\\ =x^2-3x-30\end{array}$

Step 3. Conclusion.

The simple form of the given expression is $x^2-3x-30$.

So, the equivalent of the given expression is $x^2-3x-30$.

Hence, the correct option is F.