in standard form:
you have to buy 3 dictionaries, so put a 3 next to the a (dictionaries) so that you can multiply them by each other.
a3+b= 60 (the amount of money you have)
we already know the cost of a=15 so replace a with $15
($15 x 3)+b=60
multiply 15 and 3 to get $45 and replace it with $45
and then replace b with 15 to get the total:
that means you have $15 left after buying 3 dictionaries.
15 divided by the cost of a map ($5) equals 3.
so you can buy 3 maps.
sorry if it was confusing!
nswer: a y-axis