若元素a, b, c, d, e, f依次进栈，允许进栈、退栈操作交替进行，但不允许连续三次进行退栈操作， 则不可能得到的出栈序列是（ ）。 d, c, e, b, f, a

c, b, d, a, e, f

b, c, a, e, f, d

a, f, e, d, c, b

Janie has $3. she earns $1.20 for each chore she does and can do fractions of chores. she wants to earn enough money to buy a cd for $13.50. write an inequality to determine the number of chores, c, janie could do to have enough money to buy the cd.

Which value would be a solution for x in the inequality 47-4x< 7

The length of a rectangle is x times the square root of 100. the width is one-half y more than three-halves x. given that the area of the rectangle is 125 cm2, which equation could represent the rectangle in terms of x and y? a) 5xy − 15x = 125 b) 5xy + 15x = 125 c) 15x2 − 5xy = 125 d) 15x2 + 5xy = 125