Answer:
-3y
Explanation:
-15(y2)4 ÷5y3y4
Rewrite the division as a fraction
-15(y2)4
 5y3y4
Multiply y3 by y4 by adding the exponents
-5(y2)4
 5y7
Cancel the common factor of -15 and 5
-3(y2)4
 y7
Multiply the exponents in (y2)4
-3y8
 y7
Cancel the common factor of y8 and y7
Factor y7 out of -3y8
y7(-3y)
 y7
Multiply by 1
y7(-3y)
 y7 × 1
Cancel the common factor which is y7 and y7
Rewrite the expression
-3y
 1
Divide -3y by 1 
-3y