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help me with this question

by sana.noor » Thu Aug 22, 2013 11:10 pm
In rectangular coordinate system, a straight line has a point (c,d) in the first quadrant. Does the line have a negative slope?
1) the straight line also crosses (c+2, d-3)
2) this straight line's x-intercept is greater than y-intercept

OA is A but what if we have c=6 and d=2 then according to statement one c+d = 6+2 = 8 and d-3= 2-3 = -1------>it will have positive slope. so for me it should be E
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by [email protected] » Thu Aug 22, 2013 11:59 pm
Hi sana.noor,

Using your example (c = 6, d = 2), you'd have these two co-ordinates: (6,2) and (8,-1). Graph them then connect them (since they're on the same line). Looking at the picture, what kind of slope does it have?

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by sana.noor » Fri Aug 23, 2013 5:47 am
it has negative slope
i have learned somewhere that if the slope of the line is negative and y-intercept is also negative then line passes through III quadrant. however, this line passes through I, II and IV quadrant.
and also some where on this forum i read that if x= positive and y = negative then the line will have positive slope.
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by [email protected] » Fri Aug 23, 2013 10:10 am
Hi sana.noor,

Yes, IF the slope of a line is negative and IF it's y-intercept is negative, then it will pass through quadrant III (and II and IV).

The line that you've created DOESN'T have a negative y-intercept though, it only has a negative slope (which means it's guaranteed to pass through quadrants II and IV).

With your last sentence, you need to include some words that are not currently there:

IF a line has a positive X-INTERCEPT and a negative Y-INTERCEPT, then the line has a positive slope.

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by sana.noor » Fri Aug 23, 2013 8:30 pm
y-intercept stands for b? (y=mx+b) and if we have two points x,y (8,-1) then -1 doesnt mean that y-intercept is negative (-1)?
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by [email protected] » Sat Aug 24, 2013 12:29 am
Hi sana.noor,

There's a difference between Y-INTERCEPT and Y-COORDINATE

The Y-INTERCEPT is the point (0, ?); it's WHERE the line hits the y-intercept and is represented by the "b" in y = mx + b

A Y-COORDINATE is the the second number in a co-ordinate pair; (8, -1) has a Y-COORDINATE of -1. You can graph this point, but it does not tell you what the y-intercept is.

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