Question 796485
Hi there, firstly consider the number to be variable 'x' and then write an equation of what you are wanting to solve with...

equation: 5x - 3 = 12

now it is just a matter of algebra solving

5x - 3 = 12
5x = 12 + 3
5x = 15
x = 15/5
therefore x = 3

you can then put this number into x if you wish to check that it works out
5(3) - 3 = 15 - 3 = 12

problem solved :)