1. Translate the following sentence into an equation,

A number n added to 18 is seven times the difference of n and three.

n+18=7 (n-3)

Step-by-step explanation:

Lets replace "A number" with the variable n because we do not know its value!

1) Rewrite the problem as an equation

n+18=7 (n-3)

If we want to solve the equation, do the following:

1) Distribute 7 to n and - 3:

n+18=7n-21

2) Add 21 to both sides:

n+39=7n

3) Subtract n from both sides:

39=6n

4) Divide both sides by 6:

n=6.5