SOLUTION: Find the slope and the y-intercept of each line whose equation is given. m = −3; (−2,1) SOMEONE PLEASE HELP !!!!!!!!!!!

Algebra ->  Graphs -> SOLUTION: Find the slope and the y-intercept of each line whose equation is given. m = −3; (−2,1) SOMEONE PLEASE HELP !!!!!!!!!!!      Log On


   



Question 387552: Find the slope and the y-intercept of each line whose equation is given. m = −3; (−2,1) SOMEONE PLEASE HELP !!!!!!!!!!!
Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
m is the slope and the line is passing through the point (x,y) = (-2,1)
This means that x = -2 and y = 1 at that point on the graph.
the slope intercept form of the equation of a straight line is y = m*x + b
m is the slope
b is the y-intercept
replace m with -3 to get:
y = -3x + b
replace y with 1 and x with -2 and then solve for b.
you get:
1 = -3*(-2) + b
this becomes:
1 = 6 + b
this results in b = -5
your equation becomes:
y = -3x - 5
graph of your equation looks like this:
graph%28600%2C600%2C-5%2C5%2C-15%2C15%2C-3x-5%29

you can see that the graph passes through the point (-2,1)
when x = -2, y = -3*(-2) - 5 = 6 - 5 = 1
since the slope is -3, then for every + 1 unit change in the value of x, the value of y should change by - 3 units.
when x = 0, y = -5.
when x = 1, y = -8.
when x = 1, y = -11.
etc.