Answer:
Michelle.
Step-by-step explanation:
<u>D'Andre's Bank Account: </u>
Remember to find the line, you need to use the formula y=mx+b. The m stands for slope while the b is the y-intercept. For D'Andre's y-intercept we can see that it's 0 and the slope is 2 (you can find it by doing rise/run). His equation is y = 2x.
To find how long it'll take him to get to $500, plug 500 into y: 500 = 2x
Divide by 2 on both sides: 250 = x
It'll take D'Andre 250 months to reach $500.
<u>Fiona's Bank Account:</u>
Unlike D'Andre's graph, she already has the equation, except that it isn't in the easiest form. To get it back to what it was, add 12x to the other side of the equation:
y - 12x = 100**
+ 12x = +12x
y = 12x + 100
**Just in case you didn't know, the 100 just means that's how much money she had started out with.
Plug in 500 for y: 500 = 12x +100
Subtract 100 from both sides: 400 = 12x
Divide by 12 to get x alone: 100/3 = x
It'll take Fiona about 33 months to reach $500.
<u>Sam's Bank Account:</u>
Sam has a table for his account, so we need to subtract some of the y coordinates to find his slope. Using 60 and 45 difference, we get 15. Looking at the table I can tell that is the slope because 15 is continually being added. To find his y - intercept, we need to look when his x coordinates was a 0. Therefore, his y-intercept is 60. His equation is y = 15x + 60
Plug in 500 for y: 500 = 15x + 60
Subtract 60 from both sides: 440 = 15x
Divide by 15 to get x by itself: 88/3 = x
It'll take Sam about 29 months to reach $500.
<u>Michelle's Bank Account:</u>
Last we have Michelle. Since she started with 25 dollars, that'll be her y-intercept. It also says that she is depositing 25 dollars per month, meaning 25 is her slope. Her equation should look like y = 25x + 25.
Plug in 500 for y: 500 = 25x + 25
Subtract 25 from both sides: 475 = 25x
Divide 25 from both sides to get x isolated: x = 19
It'll take Michelle 19 months to get $500.
So, in the end, Michelle will reach $500 dollars first.
