Question

Fifteen more than half a number is 9

Answer 1

`x-\ number\\\\ (1)/(2)x+15=9\ \ \ \ | subtract\ 15\\\\ (1)/(2)x=-6\ \ \ | multiply\ by\ 2\\\\ x=-12\\\\Number\ is\ -12.`

Answer 2

For this case, the first thing we must do is define a variable.

We have then:

x: unknown number

We now write the equation that models the problem:

`image`

From here, we clear the value of x.

We multiply both sides of the equation by 2:

`image`

We subtract 30 on both sides of the equation:

`image`

Answer:

The value of the unknown number is given by:

`x = -12`