So we know that the number x is multiplied by 4, and then is bigger then itself by 45, so so lets set up this equation.
4x = x + 45
The 4x is our x multiplied by 4 and the x + 45 is when it exceeds itself by 45.
Now lets solve:
4x = x + 45
Bring x to one side to isolate the variable:
4x - x = 45
3x = 45
Now we divide the 3 from the 3x in order to fully isolate the variable:
x = 45 / 3
x = 15
Lets plug 15 in to double check the answer:
4(15) = 15 + 45
60 = 60
Yes!
This means that 15 is the number multiplied by 4 and exceeded by 45.
I hope this helps! :)