SOLUTION: Find the equation of the line that passes through the points (-2, 3) and (1, -6). A. y = -9x + 3 B. y = -3x - 3 C. y = -3x + 3 D. y = -3x + 9 2. Find the

Algebra ->  Linear-equations -> SOLUTION: Find the equation of the line that passes through the points (-2, 3) and (1, -6). A. y = -9x + 3 B. y = -3x - 3 C. y = -3x + 3 D. y = -3x + 9 2. Find the       Log On


   

Question 762742: Find the equation of the line that passes through the points (-2, 3) and (1, -6).

A. y = -9x + 3
B. y = -3x - 3

C. y = -3x + 3

D. y = -3x + 9

2.
Find the equation of the horizontal line that passes through the point (-2.5, -6.3).

A. y = -2.5

B. y = -6.3x

C. y = -6.3

D. y = 0


Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
I'll do the first one to get you started


First let's find the slope of the line through the points and


Note: is the first point . So this means that x%5B1%5D=-2 and y%5B1%5D=3.
Also, is the second point . So this means that x%5B2%5D=1 and y%5B2%5D=-6.


m=%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29 Start with the slope formula.


m=%28-6-3%29%2F%281--2%29 Plug in y%5B2%5D=-6, y%5B1%5D=3, x%5B2%5D=1, and x%5B1%5D=-2


m=%28-9%29%2F%281--2%29 Subtract 3 from -6 to get -9


m=%28-9%29%2F%283%29 Subtract -2 from 1 to get 3


m=-3 Reduce


So the slope of the line that goes through the points and is m=-3


Now let's use the point slope formula:


y-y%5B1%5D=m%28x-x%5B1%5D%29 Start with the point slope formula


y-3=-3%28x--2%29 Plug in m=-3, x%5B1%5D=-2, and y%5B1%5D=3


y-3=-3%28x%2B2%29 Rewrite x--2 as x%2B2


y-3=-3x%2B-3%282%29 Distribute


y-3=-3x-6 Multiply


y=-3x-6%2B3 Add 3 to both sides.


y=-3x-3 Combine like terms.


So the equation that goes through the points and is y=-3x-3


Notice how the graph of y=-3x-3 goes through the points and . So this visually verifies our answer.
Graph of y=-3x-3 through the points and