I need help with math, giving 15 points! (And brainiest)

Answer:
C
Step-by-step explanation:
3x + y + x - 6 + y
3x + x + y + y - 6
4x + 2y - 6
Answer:
c
Step-by-step explanation:
expression c is
3x + y + x - 6 + y ← collect like terms
= 3x + x + y + y - 6
= 4x + 2y - 6