5th grade math
posted by casey .
get each variable by itself on one side of the equation.
x45=90
n+23.4=36.9

I'll show you how to work this kind of problem.
n+23.4=36.9
You want to get the knowns on one side and the unknown on the other side.
Subtract 23 from both sides.
n = 36.9  23.4
n = 13.5
I'll be glad to check your work on the first problem.
Note: you'll need to add 45 to both sides. 
13 ;5

mrow