Question

Find the values of x in this equation: x – 15 / x = 2.

A) -7, 3

B) -5, 2

C) -7, 5

D) -2, 5

E) -3, 5

Answer 1

E) -3, 5

Explanation:

x – 15 / x = 2

x^2 - 15 = 2x

x^2 - 2x - 15 = 0

(x - 5)(x + 3) = 0

x - 5 = 0; x = 5

x + 3 = 0; x = -3

Solutions: -3, 5

Answer 2

For this case we must solve the following equation:

`x- \frac {15} {x} = 2`

We manipulate the equation algebraically:

`\frac {x ^ 2-15} {x} = 2\\x ^ 2-15 = 2x\\x ^ 2-2x-15 = 0`

To solve, we factor the equation. We must find two numbers that when multiplied by -15 and when summed by -2. These numbers are:

+3 and -5.

`(x + 3) (x-5) = 0`

So, the roots are:

`x_ {1} = - 3\\x_ {2} = 5`

Answer:

Option E