Question

5(x+y)-(x+y)
5X+15Y-X+Y
answer 6x-15y

Us this correct

Answer 1

no, how can 5x - x = 6x ?
if you have 5 apples and take one away .....


5(x+y)-(x+y)
= 5x + 5y - x - y
= ...

Answer 2

the answer is 4x-14y

Answer 3

no it isn't

5(x+y)-(x+y)
= 5x + 5y - x - y
= 4x - 4y

but

15(x+y)-(x+y)
= 15x + 15y - x - y
= 14x - 14y

so you clearly had a typo in your original post