Question

Seven less than a number is negative nine.

Answer 1

Number =
`-2`

Explanation:

Let x = unknown number

Seven less than the unknown number:

`x -7 = -9`

x has to be isolated and made the subject of the equation:

`x = -9+7`

x =
`-2`

Answer 2

Explanation:

if number is x and x-7=-9

x=-2