Cell phone Plan A costs $70 per month and comes with a free $500 phone.

Cell phone Plan B costs $50 per month but does not come with a phone.

If you buy the $500 phone and choose Plan B, how many months is it until your cost is the same as Plan A's?

Priya and Han are biking in the same direction on the same path.

1. Han is riding at a constant speed of 16 miles per hour. Write an expression that shows how many miles Han has gone after hours.
2. Priya started riding a half hour before Han. If Han has been riding for hours, how long has Priya been riding?
3. Priya is riding at a constant speed of 12 miles per hour. Write an expression that shows how many miles Priya has gone after Han has been riding for hours.
4. Use your expressions to find when Han and Priya meet.

Which story matches the equation ?

For what value of do the expressions and have the same value?

Decide whether each equation is true for all, one, or no values of .

Solve each equation. Explain your reasoning.