Answer
$11.9y^{2}+3.4y+3.9$
Work Step by Step
We are asked to add $(9.3y^{2}-y+12.8)+(2.6y^{2}+4.4y-8.9)$. We can combine like terms to add.
So we bring the terms with the same power/exponent together and add their coffiecients
$(9.3y^{2} +2.6y^{2})+(4.4y-y)+(12.8-8.9)$
12.8 and 8.9 were added as they have no power of y
