slope intercept

Question

Write the slope intercept form of the equation of the line through the given points

(0,3) and (5,-1)

(3,-5) and parallel to y=-x-5

Answer 1

Part 1: (0,3) and (5,-1):

 

m = (y₂ - y₁) / (x₂ - x₁) = (-1 - 3) / (5 - 0) = -4/5

 

b = 3 because of the (0,3) point being the site of the y-intercept.

 

Thus y = (-4/5)x + 3.

 

 

Part 2: (3,-5) and parallel to y= -x - 5.

 

m = -1 for the given line, so the line you need is y = -x + b.

 

Plug in the point

 

-5 = -3 + b

 

b = -5 + 3 = -2

 

So you get y = -x - 2.

Answer 2

1. remember the formula y=mx+b

m=slope and b=y intercept

your point passes through (0,3) therefore the y intercept is 3

b=3

the equation for slope is (y1-y2)/(x2-x1).

This gives us a slope of -4/5

so your equation would be 

y=(-4/5)x+3