There is no solution for the first one
if you eliminate y you get 2 equations
-13x - 13z = -25
-13x - 13x = -15
- there is no solution to theses
a23 means the element in the second row and the 3rd column
so its -5
Thank you very much and this “question” was very helpful for me.
I think its D since it’s known that if today is Tuesday tomorrow will be Thursday
80% is the same as 4/5, so 4/5 of the class= 20. That means that if there was a picture, 4 parts would be shaded, and 1 would not. 1/4 of 20 is 5, so 1 part= 5 people. 5 x 5 = 25. 25 is the answer. :)