Question

What is the equation of the line that passes through the points: (1,-2) and (3,-8)

Answer 1

Explanation:

`y-y_(1)=(y_(2)-y_(1))/(x_(2)-x_(1)) (x-x_(1))\\y+2= \frac {-8+2}{3-1} (x-1)\\y+2=-3(x-1)\\or~y=-3x+3-2\\or~y=-3x+1`

Answer 2

y = -3x + 1

Explanation:

Step 1: Determine what the values of x1, x2, y1, y2 are

To find the slope use the formula, m =
`(y2-y1)/(x2-x1)`

(x1, y1) is (1, -2)

(x2, y2) is (3, -8)

Step 2: Plug into the slope formula

m =
`(y2-y1)/(x2-x1)`

m =
`(-8 - (-2))/(3-1)`

m =
`(-8 + 2)/(2)`

m =
`(-6)/(2)`

m = -3

Step 3: Determine what the values of y1, m, x1 in the point slope form

(y - y1) = m(x - x1)

(x1, y1) is (1, -2)

m = -3

Step 4: Plug into the point slope form

(y - y1) = m(x - x1)

(y - (-2)) = -3(x - 1)

y + 2 - 2 = -3x + 3 - 2

y = -3x + 1

Answer: y = -3x + 1