Answer:
1) 3a + 3b
2) 3a + 4b
3) 5a +3c
4) 3a + 3b
5) 7a + 2b
6) 4a + 4c
7) 7c +4d
8) 2a + 6b
Step-by-step explanation:
1) 2a + a + 3b = 3a + 3b
2) 2a + 2b + a + 2b = 3a + 4b
3) 3a + 2c + 2a + c = 5a +3c
4) a + 2b + 2a + b = 3a + 3b
5) 4a + b + 3a + b = 7a + 2b
6) 3a + 2c + 2c + a = 4a + 4c
7) 3d + 2c + d + 5c = 7c +4d
8) a + 2b + a + 3b + b = 2a + 6b
There is a 1/3 chance. Add up the shaded parts for a total of 120 degrees. 120/360 is 1/3
The X coordinates are the bottom part of a graph and Y coordinates are at the up & down part of a graph. Hopefully that answers your question.
We have two numbers say a, b. And a system of equations.

It looks a bit intimidating but it's actually very easy.
Instead of term a + b in the second equation we can say it's zero because the first equation describes a + b as being equal to 0.
So,

The above equation is not true therefore numbers a and b do not exists in the real number domain.

No solution.
Hope this helps.