Question 80344: Write the equation of the line passing through (-2,5) and (1,3). Answer must be written in slope intercept form. HELP ME!!! ;0(
Found 2 solutions by checkley75, Edwin McCravy:
Answer by checkley75(3666)   (Show Source):
You can put this solution on YOUR website! FIRST WE NEED TO FIND THE SLOPE (m) THUS:
(Y2-Y1)/(X2-X1)=(3-5)/(1+2)=-2/3 WHICH IS THE SLOPE (m).
NOW WE REPLACE X & Y IN THE EQUATION Y=mX+b & SOLVE FOR THE Y INTERCEPT (b)
5=-2/3*-2+b
5=4/3+b
b=5-4/3
b=(15-4/3)
b=11/3 THUIS IS THE Y INTERCEPT.
THUS THE LINE EQUATION IS
Y=-2/3X+11/3
 (graph 300x200 pixels, x from -6 to 5, y from -10 to 10, y = -2x/3 +11/3).
Answer by Edwin McCravy(20055)  (Show Source):
You can put this solution on YOUR website! Write the equation of the line passing through (-2,5) and (1,3).
Answer must be written in slope intercept form. HELP ME!!! ;0
We first plot those two points and draw a line
through them to find out if it is vertical or
not. The equations of all lines can be placed
in slope-intercept form except the equations
for vertical lines. This is the graph we get:
We see that it is not vertical. So we can proceed
as usual:
We are to find an equation of the line containing
the points (-2,5) and (1,3).
Use the slope formula:
y2 - y1
m = —————————
x2 - x1
where (x1, y1) = (-2,5) and (x2, y2) = (1, 3)
(3) - (5) -2 -2 2
m = —————————— = ————— = ———— = - ———
(1) - (-2) 1+2 3 3
Now substitute in the point slope formula:
y - y1 = m(x - x1)
2
y - 5 = - ———(x - (-2) )
3
2
y - 5 = - ———(x + 2)
3
Solve for y. Distribute to remove
the parentheses:
2 4
y - 5 = - ——— x - ———
3 3
2 4
y = - ——— x - ——— + 5
3 3
Put the 5 over 1
2 4 5
y = - ——— x - ——— + ———
3 3 1
Combine the last two terms by getting
the common denominator 3:
2 4 15
y = - ——— x - ——— + ————
3 3 3
2 11
y = - ——— x + ————
3 3
That's the equation in the slope-intercept
form because we can compare it with
y = mx + b
and see that its slope m is  and its
y-intercept (0,b) is the point (0, )
Edwin
|
|
|
