Question: Use Intercept to Find Slope

Comment on Use Intercept to Find Slope

Hi Brent,

When looking at this, my mind went:
1) y intercept = -2 and we're given that c = 3a/2
2) in y intercept form the component of x = slope (in this case component of x = a) and c is the y intercept
3) therefore 3a/2=-2 so solve for a=-4/3

Is this logic sound?
greenlight-admin's picture

Yes, that does yield the correct answer, but it should be noted that the y-intercept of the line is NOT equal to c (as you suggest). The y-intercept = c/b

Hi Brent,

Is the below approach correct?
Since y intercept is -2, we can conclude that y = -2 & x = 0.
Therefore substituting the above value in the equation along with c = 3a/2 we get
y = (a/b).x + (c/b)
-2 = (a/b).0 + 3a/2b
-2 = 3a/2b
a/b = -4/3
Therefore slope = a/b = -4/3
greenlight-admin's picture

Perfect approach!!!

I solved it like this; since c is -2 and c=3a/2,then -2=3a/2 Then i solved for "a" which is the slope of the line by multiplying both sides by 2 to get -4=3a then a=-4/3
greenlight-admin's picture

Your solution is similar, except I first show that c is the y-intercept and a/b = slope (not "a" as you suggest).

Nevertheless, good work!

Cheers,
Brent

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