Question

if the sum of a number and nine is doubled, the result is seven less than the number. find the number.

Answer 1

X=the number we have to find.
This expression "2(x+9)" is when the sum of a number and nine is doubled.
If the result is seven less than the number, we will have: x-7

We can suggest the following equation:
2(x+9)=(x-7)
2x+18=x-7
2x-x=-7-18
x=-25

answer: the number would be:  -25.