y = 15x + 10
Explanation:
Given a graph, we use the equation of line y = mx + b
m = slope
b = y-intercept
First let's find the slope using the formula:
[tex]m\text{ = }\frac{y_2-y_1}{x_2-x_1}[/tex][tex]\begin{gathered} u\sin g\text{ any two points on the line: } \\ (2,40)\text{ and (4, 70)} \\ x_1=2,y_1=40,x_2=4,y_2\text{ = }70 \\ m\text{ = slope = }\frac{70-40}{4-2} \\ \text{slope = }\frac{30}{2}\text{ = 15} \end{gathered}[/tex]
The y-intercept is the value of y when x = 0. It is also the value of y when the line crosses the y-axis.
The value of cost when time is zero
The line crosses the y-axis at y = 10
Hence, the y-intercept is 10
The equation of line becomes:
y = 15x + 10
