2y^4 and 5y^4 because same variable (y), same degree (3)
The answer is f=3. You get this by combining like terms.
So you have to simplify
(9 x 10 x 18) 2 + (5 x 10 x 18) (-7) + (5 x 9 x 18)
(-11) + (5 x 9 x 10)
5 x 9 x 10 x 18
1620 x 2 + 900 (-7) + 810(-11) + 450 x 5
x 5 x 9 x 10 x 18
The answer would be -6/5
