单选题 Two boards are being cut for a construction project. If the total length of the boards is 100 inches and the shorter board is 5 inches less than half the length of the longer board, what is the length of the shorter board?
25 inches
30 inches
35 inches
65 inches
70 inches
单选题 If r is negative and s is positive, which of the following must be negative?
r2+s
r2s2
单选题 ______.
21
42
58
单选题 Which of the following could be the equation of line l in the following figure?
2x=3y-2
2x=3y-6
3x=2y-6