What is the characteristic of a Matrix Null

Select the appropriate response:

A) All elements are = 0
B) All elements are negative
C) First row = 0
D) First Column = 0

Help please!

What is the value of  y  in the solution to the system of equations? x  +  y  =  12x  –  3y  =  –30a. –8b. –3c. 3d. 8

The answer is 7.2 how would you put this as money

The oates family went out for dinner the price of the meal was $33.95 the sales tax was 7.25% of the price of the meal . the tip was 15% of the meal and the sales tax . how much money did the oates family pay for the meal, including tax and tip