Answer:
the answer should be 12
Step-by-step explanation:
Answer:
(a) The system of the equations
has no solution.
(b) The system of the equations
has many solutions 
Step-by-step explanation:
(a) To find the solutions of the following system of equations
you must:
Multiply
by 2:

Subtract the equations

0 = -3 is false, therefore the system of the equations has no solution.
(b) To find the solutions of the system
you must:
Isolate x for 

Substitute
into the second equation

The system has many solutions.
Isolate y for 

4000 is his total monthly balance.
420 + 380 = 800
800/4000 = 0.20
0.20 = 20%
He spent 20% of his monthly income on food and personal items.
The point (-1,2) is in quadrant 2