Question

Complete the equation of the line through (2, 1) and (5, -8). Use exact numbers. y =​

Answer 1

y = - 3x + 7

Explanation:

The equation of a line in slope- intercept form is

y = mx + c ( m is the slope and c the y- intercept )

Calculate m using the slope formula

m =
`(y_(2)-y_(1) )/(x_(2)-x_(1) )`

with (x₁, y₁ ) = (2, 1) and (x₂, y₂ ) = (5, - 8)

m =
`(-8-1)/(5-2)` =
`(-9)/(3)` = - 3 , then

y = - 3x + c ← is the partial equation

To find c substitute either of the 2 points into the partial equation

Using (2, 1 ), then

1 = - 6 + c ⇒ c = 1 + 6 = 7

y = - 3x + 7 ← equation of line

Answer 2

Explanation:

given: (2,1) & (5-8)

first find the slope,

m= (Y2-Y1) / (X2-X1)

m=(-8-1)/(5-2)

m=(-9)/(3)

m=-3

we have y=-3x+b

use any point to sub in x and y

1=-3(2)+b

1+6=b

b=7 therefore, y=-3x+7 is the equation