Question 165803: what is the slope and the y intercept of
3y+3x+1=0
Found 2 solutions by Fombitz, gonzo:
Answer by Fombitz(32388)   (Show Source):
Answer by gonzo(654)  (Show Source):
You can put this solution on YOUR website! the easiest way to find it is to convert the equation into the slope intercept form.
that form is: y = m*x + b
where m is the slope and b is the y intercept.
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your equation is:
3y + 3x + 1 = 0
subtract one from both sides.
3y + 3x = -1
subtract 3x from both sides
3y = -3x - 1
divide both sides by 3
y = (-3x-1)/3
remove parentheses
y = -3x/3 -1/3
simplify
y = -x - 1/3
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that's the slope intercept form
the slope is -1
the y intercept is -1/3. that's where the line crosses the y axis (x = 0)
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here's what the equation looks like on the graph.
look below the graph for further comments.
you can see that the line intersects the y axis at -1/3 which is the y intercept which is the value of y when x = 0.
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plotting some points from the equation will show them to be on the graph where expected.
x, y
-4, 3+2/3
-2, 1+2/3
0, -1/3
2, -2-2/3
4, -4-1/3
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you can take any 2 points on the line and solve for the slope.
i picked (-4,3+2/3) and (4,-4-1/3)
the slope is calculated using the formula (y2-y1)/(x2-x1)
let (x1,y1) = (-4, 3+2/3)
let (x2,y2) = (4, -4-1/3)
change the improper fractions into proper fractions.
(x1,y1) = (-4,11/3)
(x2,y2) = (4,-13/3)
place in the formula and solve for the slope.
[(-13/3) - (11/3)] / [(4) - (-4)]
becomes
(-24/3) / 8
becomes
-8/8
becomes
-1
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