SOLUTION: Help me solve this equation.Find the equation of the line through (-2,-9) and (0,-6).Write the equation in standard form.I have tried -9-(-6)

Algebra ->  Linear-equations -> SOLUTION: Help me solve this equation.Find the equation of the line through (-2,-9) and (0,-6).Write the equation in standard form.I have tried -9-(-6)       Log On


   

Question 226454: Help me solve this equation.Find the equation of the line through (-2,-9) and (0,-6).Write the equation in standard form.I have tried -9-(-6)
-2-0 and i get -3/-2
so then i put it in -9=-3/2(-2)+b and i get y=-3/2x-12 and my final answer is 3x+2y=-24 but that is not one of the choices given to me. Can you tell me what is it that i'm doing wrong
Found 2 solutions by scott8148, jim_thompson5910:
Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
"-2-0 and i get -3/-2
so then i put it in -9=-3/2(-2)+b"

you have a sign problem
-3/-2 is 3/2 (the negatives cancel)
you use -3/2 in your equation

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

First let's find the slope of the line through the points and


m=%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29 Start with the slope formula.


m=%28-6--9%29%2F%280--2%29 Plug in y%5B2%5D=-6, y%5B1%5D=-9, x%5B2%5D=0, and x%5B1%5D=-2


m=%283%29%2F%280--2%29 Subtract -9 from -6 to get 3


m=%283%29%2F%282%29 Subtract -2 from 0 to get 2


So the slope of the line that goes through the points and is m=3%2F2


Now let's use y=mx%2Bb and m=3%2F2 to find 'b'


y=mx%2Bb Start with the general slope-intercept equation.


y=%283%2F2%29x%2Bb Plug in the given slope m=3%2F2.


-9=3%2F2%28-2%29%2Bb Plug in the x=-2 and y=-9 from the given point .


-9=-3%2Bb Multiply 3%2F2 and -2 to get -3


-9%2B3=b Add 3 to both sides.


-6=b Combine like terms.


So the y-intercept is b=-6.


So the equation (in slope-intercept form) that goes through the points and is y=%283%2F2%29x-6


If you need to convert it into standard form, then...


y=%283%2F2%29x-6 Start with the slope-intercept equation.


2y=3x-12 Multiply EVERY term by the LCD 2 to clear the fraction.


-3x%2B2y=-12 Subtract 3x from both sides.


3x-2y=12 Multiply EVERY term by -1 to make the x coefficient positive.


So the equation in standard form that goes through (-2,-9) and (0,-6) is 3x-2y=12


Here's a graph to visually confirm our answer: