2x +5y = 24 l≤x≤3 Column A Column B x y A.if the quantity in Column A is greater B.if the quantity in Column B is greater C.if the two quantity are equal D.if the relationship cannot be determined from the information given
A.if B.if C.if D.if
【参考答案】
B 解析:本题的正确为(B)。因为2x+5y=24是一条直线方程,因此考生可以用边界条件法进行求解,所谓边界条件法,就是只取x区间的两端判断y的区间:z=1时,y=5.4;x=3时,y=3.6,由此可以得出:3.6≤y≤5.4