Answer
$a. 3y$
$b. 2y²$
$c. -3y$
$d. 2y²$
Work Step by Step
a. When adding like terms you add the coefficients $2+1=3$.
b. When multiplying monomials you multiply the coefficients and the variables, then you multiply those two products $2\times1=2$ &
$(y)\times(y)=y²$.
c. Same as a. $-2+-1=-3$
d. Same as b. $-2\times-1=2$ & $(y)\times(y)=y²$
