In the xy-plane, does the line with equation y = 3x + 2 contain the point (r, s) ?
(1) (3r + 2 - s)(4r + 9 - s) = 0
(2) (4r - 6 - s)(3r + 2 - s) = 0
Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
EACH statement ALONE is sufficient.
Statements (1) and (2) TOGETHER are NOT sufficient.
y=3x+2 will contain (r,s) only if s=3r+2.
(1) s=3r+2 OR 4r+9. Insuff.
(2) s=4r-6 OR 3r+2. Insuff.
Combining: s=3r+2. Suff. C
(1)+(2) Both 4r+9−s=04r+9−s=0 and 4r−6−s=04r−6−s=0 cannot be true (simultaneously), as 4r−s4r−s can not equal to both -9 and 6, hence 3r+2−s=03r+2−s=0 must be true. Sufficient.
联立1和2得S=3r+2
易错题
(1)+(2) Both 4r+9−s=04r+9−s=0 and 4r−6−s=04r−6−s=0 cannot be true (simultaneously), as 4r−s4r−s can not equal to both -9 and 6, hence 3r+2−s=03r+2−s=0 must be true. Sufficient.