Let's say the two points, or coordinates are (-2, 8) and (6, -8). How do you find the y-intercept of a line from just those points? is there some way to do it without graphing? I know the slope is -2.
2007-02-01 12:04:50 · 5 answers · asked by callie =] 2 in Education & Reference ➔ Homework Help
you have to plug in the points and slope into the equation y=mx+b
y is one of the y-cooirdinates, m is the slope, x is one of the x coordinates (same one as you plugged in for y) and b is the y-intercept.
8=(-2)(-2)+b
8=4+b
b=4
2007-02-01 12:09:41 · answer #1 · answered by anqi_yu 3 · 0⤊ 0⤋
You need to find the equation of the line. (y-y)/(x-x)
(8 - -8)/(-2 -6) = 16/-8 = -2 <----is the slope of the line
so y =-2x + b <----is the y-intercept
now you just plug in one of your points to solve for the y intercept:
8 = -2(-2) + b
8 = 4 + b
4 = b
so the equation is y = -2x + 4 where 4 is your y intercept
2007-02-01 12:18:57 · answer #2 · answered by pocahontas 1 · 0⤊ 0⤋
You set it up into slope intercept form. First, take the points into y-y1 = m(x-x1). Then into y = mx + b. Problem is worked out below.
2007-02-01 12:14:11 · answer #3 · answered by Ironica 2 · 0⤊ 0⤋
use point slope form
y-y1=m(x-x1)
The 8 would be the y-intercept
2007-02-01 12:23:19 · answer #4 · answered by Nurse KeVo 5 · 0⤊ 0⤋
use point slope form
y-y1=m(x-x1)
The 8 would be the y-intercept
2007-02-01 12:09:45 · answer #5 · answered by VdogNcrck 4 · 1⤊ 0⤋