Data Sufficiency

In the XY-coordinate plane, line l and k intersect at the point (4,3). Is the product of their slopes negative?

1) the product of the x intercepts of lines l and k is positive
2) the product of the y-intercepts of lines l and k is negative


The answer is c) Both

Please explain.

Let the two lines be

Y = Mx + C --- 1
Y = Ax + B --- 2

So Slope of line 1 is M , Line 2 is A.
X intercepts being -C/M , -B/A

Product of slopes --> MA.

ST-1

the product of the x intercepts of lines l and k is positive
i,e CB/MA is -ve.

Nothing can be derived

ST-2

the product of the y-intercepts of lines l and k is negative
i,e CB is -ve nothing can be derived


ST-1,ST-2

combining both MA has to be -ve ...

So that is we are ought to check

Ans; C

Keep rockin !

I assume you meant to say that MA is +ve.