Question

What is the equations of the line passing through points (-3,7) and (9,-1)?

Answer 1

The slope-intercept form:

`y=mx+b`

m - slope

b - y-intercept

The formula of a slope:

`m=(y_2-y_1)/(x_2-x_1)`

We have the points (-3, 7) and (9, -1). Substitute:

`m=(-1-7)/(9-(-3))=(-8)/(12)=-(2)/(3)`

Therefore we have

`y=-(2)/(3)x+b`

Put the coordinates of the point (-3, 7) to the equation of a line:

`7=-(2)/(3)(-3)+b`

`7=2+b` subtract 2 from both sides

`5=b`

Answer:
`\boxed{y=-(2)/(3)x+5}`