Slope and y intercept

Answer:
[tex]y=\frac{25}{1}x+75[/tex]
The beginning balance of Sophie's account is 75
Step-by-step explanation:
Using the slope intercept form aka [tex]y=mx+b[/tex]
The slope of a line describes how steep a line is.
$ is how much you have in your bank account.
We can see that Sophie starts off with 75 dollars.
In the first week, we see that Sophie has 100 dollars. In the second week, we see that Sophie has 125.
[tex]slope formula\\m=\frac{rise(y)}{run(x)}=\frac{y_{2}-y_{1} }{x_{2}-x_{1} }[/tex]
The first week (1, 100)
The second week (2,125)
[tex](x_{1}, y_{1})= 1, 100\\(x_{2}, y_{2})= 2, 125\\m=\frac{125-100}{2-1}=\frac{25}{1} \\Up 25 (aka, 1 line), over 1(aka 2 lines)[/tex]