Question

What is the equation of this line in slope-intercept form?

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Answer 1

y = -3x +2

The general equation for a linear line is y = mx + b

Where:

• m = the slope of the line
• b = the y-intercept

To find the slope of a line we can use the formula
`(rise)/(run)`

Rise over run can be found suing two different points on the line.

in this case: (-1,5) and (1,-1)

The rise is the difference in y values:
`y_2 -y_1`

rise = (-1) - 5

rise = -6

run =
`x_2 - x_1`

run = 1 - (-1)

run = 2

rise/run =
`(-6)/(2)`

rise/ run = -3

We now have y = -3x + b

To find b we just look at the graph and locate a what point x = 0

• this occurs at (0,2)
• b = 2