Question

What is the equation of the line, in slope-intercept form, that contains the points (−1, 5) and (2, 2)?
y = −3x + 4
y = −x + 1
y = x + 4
y = −x + 4

Answer 1

So,

First, we need to find the slope by subtracting the y-values and subtracting the x-values.

5 - 2 = 3
-1 - 2 = -3

Now divide the y-result by the x-result.
3/-3 = -1 <-- slope

y = -x + b <-- equation so far

To find the y-intercept, substitute a solution into the equation.

2 = -2 + b

Add 2 to both sides.
4 = b

Now we have our complete equation.
y = -x + 4 <-- option D

Answer 2

y=mx+b
m=slope
b=yintercept
slope=(y2-y1)/(x2-x1)

given the points (-1,5) and (2,2)
slope=(2-5)/(2-(-1))=-3/(2+1)=-3/3=-1
y=-1x+b
sub a oint
(2,2)
x=2
y=2
2=-1(2)+b
2=-2+b
add 2
4=b

y=-x+4