Question

What value, entered in the blank below, would make the two expressions equivalent? Expres

any non-whole numbers as fractions.

-27x2 + 9x + 12 =

(9x2 – 3x – 4)

Answer 1

The value is -3

Explanation:

Here in this question, we are interested in making the expressions on both sides of the equation equal. But we seek a particular value or number which when placed in front of the quadratic expression on the right hand side makes the equations equal.

To get this done with, we will need to factorize the expression on the left hand side of the equation.

Thus, we can write;

-27x^2 + 9x + 12 as 3(-9x^2 + 3x + 4)

What do we notice? we can see that the now factored quadratic expression resembles what we have on the right hand side asides there fact that we are not there yet in terms of sign.

Thus, we can finally write ;

-27x^2 + 9x + 12 as -3(9x^2 -3x -4)

This exactly gives the expression on the right hand side

Thus the value to place in the blank is -3