Using x as the variable, if someone gets $1.50 per pizza delivered, write an equation showing how many pizzas he'd deliver to make more than $20 in tips?

To find how many pizzas the person would have to deliver to make more than $20, we must set up an inequality. The key phrase is "more than 20"; this gives you the symbol you will need, > for greater than

Now to determine our equation. 

We know the person gets 1.50 per pizza. This means if they deliver 0 pizzas, they get $0. If they deliver 2 pizzas, they get $3. And so on. Let x be the number of pizzas. The x-value is directly correlated to the 1.50 and being that the question uses the word "per," we know to multiply. 

Our equation is 1.50x > 20 or 1.50(x) > 20

To solve, divide both sides by 1.50 which isolates the variable. 20 divided by 1.50 = 13.33 with the .33 repeating. Since you can't sell a fraction of a pizza to someone, we round to the nearest pizza, 13. x > 13 would be your answer.

So the person would have to deliver more than 13 pizzas to make more than $20 in tips.