Your friend has $100 when he goes to the fair. he spends $10 to enter the fair and $20 on food. rides at the fair cost $2 per ride. which function can be used to determine how much money he has left over after x rides? f(x) = −2x 70 f(x) = 2x 70 f(x) = −2x − 70 f(x) = −30x $100