In the xy-plane, region R consists of all the points (x.y) such that 2x + 3y = 6. Is the point (r,s) in region R?
(1) 3r + 2x = 6
(2) r=3 and s=2
answer is E.
I chose B, here is my solution:
2x + 3y = 6 , so y = (-2/3)*x + 2
1) 3r + 2s = 6, so s = (-3/2)*r +3, it can intersect with stem, so insufficient
2) (2, 3), won't intersect with 2x + 3y = 6, so not in the region, sufficient
please tell me where I did wrong, thanks |