Amanda will make $75, if she watches them for seven hours
How to find the prediction
The equation graphed is written in the slope intercept form s below
y = mx + c
where
m = slope
x = intercept
The slope, m is calculated using the points on the graph (1, 15) and (3, 35)
m = (y₀ - y₁) / (x₀ - x₁)
m = (15 - 35) / (1 - 3)
m = (-20) / (-2)
m = 10
c = y intercept, from the graph
c = 5
The equation of the line is y = 10x + 5
For x = 7
y = 10 (7) + 5
y = 75