Question

the price of a hat is $12. The price of a scarf is $14. I spent $128 on 10 items. How many hats did I buy?

Answer 1

h + s = 10 ... s = 10 - h

12 h + 14 s = 128

substituting
... 12 h + 14(10 - h) = 128
... 12 h + 140 - 14 h = 128
... -2 h = -12