Peform each indicated operation and simplify. Can you please check my answers. Thank you.

A)(x^2+2x-3)+ (2x^2-x+1)
Answer: 3x^2+x-2

B) (-x^3+2x^2-5)+(x^2-x+6)
Answer:-x^3+3x^2-x+1

C) (3y^2-x+7)-(y^2-2x+3)
Answer:4y^2-3x+10

D)(2x^2-xy+y^2)-(-3x^2+xy+y^2)
Can you help me with the answer for this one Im confused. thanks

a, b right

C should be 2y^2+x-4 There is a - sign before the second ( )
d.
5x^2-2xy check that.