Question

If 18 is subtracted from twice the square of an integer, the result is equal to nine times the integer. What is the value of the integer?

Answer 1

Answer:

6 or -1.5

Step-by-step explanation:

We can let this integer be x.

Therefore, according to the question we have:

$2x^2-18=9x$

Subtracting 9x, we have a quadratic:

$2x^2-9x-18=0$

Plugging into the quadratic equation:

$\frac{9+\sqrt{81+144}}{4}, \frac{9-\sqrt{81+144}}{4},$

the square root of 81+144 is 15, so the answer is either 6 or -1.5