Meredith is playing games at an arcade to earn tickets that she can exchange for a prize. She has 294 tickets from previous visit, and she earns 7 tickets for each game she plays in the equation below, x represents the number of games Meredith plays and y represents the number of tickets she needs for the prize.

y = 7x + 294

If Meredith needs 448 tickets to exchange for the prize she wants, how many games does Meredith need to play?

A. 106

B. 19

C. 64

D. 22

An easy way to do this is by plugging in all the answers until you get your answer

y=7 (106) + 294

y=742+294

y=1036

She doesn't need this many tickets to get the one prize, so this is false

y=7 (19) + 294

y=133+294

y=427

This cannot be true, because you need to have 448 tickets

y=7 (64) + 294

y=448+294

y=742

This is still over the amount of tickets that she needs, so this isn't true

y=7 (22) + 294

y=154+294

y=448

This is exactly the number of tickets that she needs, so this is true

So the answer is D

First, plug in 448 for y:

448=7x+294

Secondly, subtract 294 from both sides to isolate x:

154=7x

Divide both sides by 7:

22=x

Refine:

x=22

The answer is D) 22