Adding and Subtracting Polynomials

1. For $i=\sqrt{-1}$, what is the sum of $(8+3i)+(9-7i)$?

1. $-1-10i$
2. $1-4i$
3. $17-4i$
4. $17+4i$

2. For $i=\sqrt{-1}$, what is the difference of $(4-2i)-(6-5i)$?

1. $-2-7i$
2. $-2-3i$
3. $-2+3i$
4. $2-3i$

3. $(y^2+xy+5xy^2)-(xy-5xy^2-y^2)$

Which if the following is equivalent to the expression above?

1. $0$
2. $2y^2$
3. $2y^2+2xy$
4. $2y^2+10xy^2$

4. $(3xy^2-x^2y+3y^2)-(-6xy^2+5x^2y-y^2)$

Which if the following is equivalent to the expression above?

1. $3xy^2-6x^2y+4y^2$
2. $9xy^2+4x^2y+4y^2$
3. $9xy^2-6x^2y+4y^2$
4. $-3xy^2-6x^2y+4y^2$