Question

A number squared subtracted from 3 times the number is equal to negative 70. Set up and solve a quadratic equation, then solve by factoring.

Answer 1

We will have the following:

From the problem we construct the expression:

$3x-x^2=-70$

Now, we solve for x:

$\begin{gathered} \Rightarrow-x^2+3x+70=0\Rightarrow-(x^2-3x-70)=0 \\ \\ \Rightarrow-(x+7)(x-10)=0 \\ \\ x=-7 \\ x=10 \end{gathered}$

The number can be either -7 or 10.