Answer:
2y² -4y +5
Explanation:
First you need to find the sum of y²+5y-1 and 3y²-2y+4
(y²+5y-1) + (3y²-2y+4) => y²+3y²+5y-2y-1+4
=4y²+3y+3
Next is to subtract 2y²+7y-2 from the sum calculated above in order to find the algebraic expression asked in the exercise
4y²+3y+3 -(2y²+7y-2) => 4y²-2y²+3y-7y+3+2
=2y² -4y +5
Therefore, the algebraic expression asked must be 2y² -4y +5