Julie went to the post office and bought both 41-cent stamps and 26-cent postcards. she spent $51.40. the number of stamps was 20 more than twice the number of postcards. how many of each did she buy? stamps= ? postcards= ?

Stamps = 100, Postcards = 40

100 x 0.41 cents + 40 x 0.26 cents = $41 + $10.4 = $51.4

Solution

$0.41 x STAMPS + $0.26 x POSTCARDS = $51.4

1 STAMP = 20 + 2 x POSTCARDS

$0.41 x (20 + 2 x POSTCARDS) + $0.26 POSTCARDS  = $51.4

POSTCARDS = 40

STAMPS = 20 + 2 x 40 = 100

given the equation is 8+9z=-6, the first step would be to subtract the 8 from both sides:

8+9z-8=-6-8

since 8 minus 8 = 0, this would cancel out the 8. and since -6 minus 8 equals -14, the equation would look like this

9z = -14