In the xy-plane, does the line with equation y=3x+2 contains the point (r,s)?
(1) : (3r+2-s)(4r+9-s) = 0
(2) : (4r-6-s)(3r+2-s) = 0
Could someone, please, help me with this? This is from the official GMAT Prep Soft (Practice test 1). The solution was quite obvious to me, but the OA surprized me.
Dont try to multiply that behemoth out. Just realize that S1: is s=3r+2
and S2: also has s=3r+2. Combined we know that s=3r+2
Sorry, could you please explain it in more details.
We have 3r+2-s, which gives us s=3r+2 in each of the conditions. I thought this means that each is suff. Thus D. Why C then?