Answer:
Choice A is correct answer.
Step-by-step explanation:
Given equation is:
x+y+3 = -2x+4y+18
Adding 2x to both sides of above equation, we get
2x+x+y+3 = 2x-2x+4y+18
3x+y+3 = 0+4y + 18
Adding -4y to both sides of above equation,we get
3x+y+3 -4y = 4y+18-4y
3x-3y+3 = 18
Adding -3 to both sides of above equation, we get
3x-3y+3-3 = 18-3
3x-3y = 15
Taking 3 common to both sides of above equation, we get
3(x-y) = 3(5)
Hence, x-y = 5 where a = 1 , b = -1 and c = 5
