Create a system if equations to solve this.
First equation:
25m + 24e = 220
Second equation:
m + e = 9
Then you must solve the second equation for a variable.
Change m + e = 9 to e = 9 - m.
Then substitute (9 - m) for e in the first equation.
So 25m +24e = 220 becomes 25m + 24(9 - m) = 220.
Now you can solve the first equation because the only variable in it is m.
25m + 24(9 - m) = 220 (Original equation)
25m + 216 - 24m = 220 (Distribute)
m + 216 = 220 (Combine like terms)
m = 4 (Simplify)
Now plug in 4 for m in the second equation.
m + e = 9 (Original equation)
(4) + e = 9 (Substitute)
e = 5 (Simplify)
m represents Math Books and e represents English Books, so Nicole purchased 4 Math Books and 5 English Books.
