Which statement illustrates the associative property of addition? Select one:

a. (1+√3)² + √7= 1 + (√3+√7) ²
b.(-2+72) + 4i - 2 + (7i+ 42)
c. v 18 + 5/3 (√6 +5)
d. (51.21) + 111 – 111 + (51-21)​

Steve wants to develop a way to find the total cost of any item including sales tax. the sales tax in his city is 6%. his friend jenna writes the expression x + 6x where x is the cost of the item. explain whether her expression is correct based on the situation.

Solve this system of equations. 12x − 18y = 27 4x − 6y = 10

When george started his current job, his employer told him that at the end of the first year, he would receive two vacation days. after each year worked, his number of vacation days will double up to five work weeks (25days) of payed vacation. how many vacation days will he have in 4 years