Correct answer D(4,2) only this one is at the pink area that is solution of this system
Answer:

Step-by-step explanation:
The required answer is the rate at which Machine A works when the two machines are combined.
Note: the rate of doing work is express as

Hence we can conclude that Machine A working rate is
and machine B working rate is

When the two machine works together, the effective working rate is

The fraction of the work that Machine B will not have complete because of Machine A help is the total work done by machine A
Hence the fraction of work done by A is expressed as


Hence the fraction of the work that Machine B will not have complete because of Machine A help is the total work done by machine A is 
Answer:
Step-by-step explanation:
1) 5 - [-5] = 5 + 5 = 10
2)8 - 13 = 8 + (-13) = -5
3) 12 +(-3) = 9
4) x + (-7) = 5
x - 7 = 5
x = 5 + 7
x = 12
We need to add 12 to (-7) to get 5
5) 7 - x = -5
7 = -5 +x
7 + 5 = x
12 = x
We need to take away 12 to 7 to get (-5)
6) 7 - (-10) = 7 + 10 = 17
17° C