Question

Write an equation for the data in the table. Identify your variables.

Answer 1

First find the slope m. slope formula: $\frac{y_{2} - y_{1} }{x_{2} - x_{1} }$

Let's use (0, -20) for x1 and y1; and (2, 10) for x2 and y2

$\frac{10-(-20)}{2-0}$ = $\frac{30}{2}$ = $15$

Now find the y-intercept: the point where the graph crosses the y-axis. The y intercept always has an x value of 0. So -20 is the y-intercept

Use the slope formula $y = mx + b$. Slope=m, y-intercept = b

y = 15x - 20

y is the money in the bank account in dollars

x is the day