While you cannot solve 946x+642y=911 for numerical values of x and y, you can indeed solve 946x+642y=911 first for x and then for y:
-911 - 642y
For x: 946x+642y=911 becomes 946x = 911 - 642y, or x = ------------------
946
911-946x
For y: 946x+642y=911 becomes 642y = 911-946x, or y = ---------------
642
Answer: 400
Step-by-step explanation:
If 5% of a number is 80, just multiply that number by 5 to get 25 (5 x 5 = 25) and you will get 400.
1h 15minutes, I converted each time into fractions, 2hours to

and the 8hour to

, this means, painter #1 finishes 1/2 of the project in 1 hour, and paither #2 finishes 1/8 of project in 1 hour, now when we make each fraction out of 2 hours, so

and

, we add them and get

, then as mixed number, 1 1/4 which is 1 hour and 15min<em>(1/4 of a hour)</em>
I believe im right.
There is the equal values method, so you can do:
x-4 = 4x-10 (remove x from both sides)
-4 = 3x -10 (add ten to both sides)
6 = 3x (devide by 3x)
2 = x
Check: (by plugging it into the equation)
y = 2-4 and y = 8-10
y = -2 and y = -2
that's matches so it is correct...
YOUR ANSWER IS:
(2, -2)
I hoped I helped sort things out, and have a great day!