In 2012, five U. S. postal stamps cost $2.20. How much did seven stamps cost? Use cross multiplication to solve the proportion.

45 minutes

step-by-step explanation:

let's solve your equation step-by-step.

4x+2=2x+12

step 1: subtract 2x from both sides.

4x+2−2x=2x+12−2x

2x+2=12

step 2: subtract 2 from both sides.

2x+2−2=12−2

2x=10

step 3: divide both sides by 2.

2x

2

=

10

2

x=5

step-by-step explanation: