Question

Find the slope and y-intercept for the equation that contains the points (0.75, 0.25) and (2.25, -0.25).

Answer 1

the slope between 2 points (x1,y1) and (x2,y2) is (y2-y1)/(x2-x1)
so slope between points (0.75,0.25) and (2.25,-0.25) is
(-0.25-0.25)/(2.25-0.75)=(-0.5)/(1.5)=-1/3

the slope is -1/3

to find y intercept
y=mx+b
b=y intercept
m=slope
put in a point
(0.75,0.25)
x=0.75, y=0.25
0.25=-1/3(0.75)+b
solve for b
0.25=-0.25+b
0.5=b

y intercept is 0.5
slope is -1/3
equation is y=(-1/3)x+0.5

Answer 2

0.25-(-0.25) 0.5 -1
----------------- = --------- = ------
0.75-2.25 -1.5 3

Plug in one of the points to your x and y for the b which should come out to be 0.
-1 -1
So the complete answer is y= ----x +0 or just y= ----x
3 3