Question

Check one of my questions & I need help with two questions.

Answer 1

The first question should be 7.

Answer 2

The second is B

Answer 3

For the second, just imagine the line is an equal sign

Answer 4

The third should be A

Answer 5

Just write the third in matrix form. (This can help you understand the second question).

Answer 6

7a-b=-1
-4a-2b=-2

thus the matrix looks like
[7 -1| -1]
[-4 -2| -2]