I’ll mark you as brainliest Heike is saving money to purchase a surfboard
that costs $250. She began with $30 and saved an
additional $10 every week, as shown on the graph
below. If he continues to save at the same rate on which week will he have saved enough money to purchase the surfboard

Okay so basically what you have to do is the function 10x+30=250. You get ten from the ten dollars he saves every week, and the weeks are represented by x. The +30 is from the thirty he started with. Since we know the answer to this is $250, we have to do inverse operations. First you subtract 30 from both sides leaving you with 10x=220. Then you divide by 10 on each side to get x=22. The answer is x=22, and like we said before x is the number of weeks, so your final answer is 22 weeks