Answer:
a) Let her comic books be x
b) as she sold half it will be
+ 8 = 13 ( as she sold half and then she bought 8 more that means plus and then now she have 13 that means = 13)
c ) to solve to find the books she have we need to
+ 8 = 13
Transpose
= 13 - 8
= 5
x = 5 × 2
x = 10
the comic books were 10
we can even cross- check to see if the value is right instead of x put 10
+ 8 = 13
5 +8 = 13
13 = 13
Cross-checked