SOLUTION: a line passes through the point (-4,-1) and has a slope of 3. Write an equation for this line.

Algebra ->  Graphs -> SOLUTION: a line passes through the point (-4,-1) and has a slope of 3. Write an equation for this line.      Log On


   

Question 1086076: a line passes through the point (-4,-1) and has a slope of 3. Write an equation for this line.
Found 4 solutions by rfer, jim_thompson5910, math_helper, MathLover1:
Answer by rfer(16322) About Me  (Show Source):
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
Point Slope Form:

y-y%5B1%5D+=+m%28x-x%5B1%5D%29

y-y%5B1%5D+=+3%28x-x%5B1%5D%29 Replace m with the given slope 3

y-y%5B1%5D+=+3%28x-%28-4%29%29 Plug in x%5B1%5D+=+-4 which is the x coordinate of the point the line goes through

y-%28-1%29+=+3%28x-%28-4%29%29 Plug in the y coordinate y%5B1%5D+=+-1 of the point the line goes through. Now solve for y.

y%2B1+=+3%28x%2B4%29

y%2B1+=+3%28x%29%2B3%284%29

y%2B1+=+3x%2B12

y%2B1-1+=+3x%2B12-1 Subtract 1 from both sides

y+=+3x%2B11 Answer in slope intercept form. We see that the y intercept is 11, meaning that the point (0,11) is also on the line.

Graph:
+graph%28+500%2C+500%2C+-10%2C+10%2C+-5%2C+15%2C+0%2C3x%2B11%29+

Answer by math_helper(2461) About Me  (Show Source):
You can put this solution on YOUR website!
Point slope form: y-y1 = m(x-x1)
Where:
m=slope
(x1,y1) = some point on the line
y - (-1) = 3(x - (-4))
y+1 = 3(x+4)
y+1 = 3x+12
+highlight%28y+=+3x+%2B+11%29+ <<< slope-intercept form (in my experience, this is the most common form)
Other equivalent forms (just re-arranging the above):
+highlight%28y%2B1+=+3%28x%2B4%29%29+ <<< point-slope form
+highlight%283x+-+y+=+-11%29+ <<< standard form

Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

a line passes through the point (-4,-1) and has a slope of 3
y+-y%5B1%5D+=+m%28x+-x%5B1%5D%29
y+-%28-1%29+=+3%28x+-%28-4%29%29
y+%2B1+=+3%28x+%2B4%29
y+%2B1+=+3x+%2B12
y+=+3x+%2B12-1
y+=+3x+%2B11