#27 can you check this:

-5x (x-4)

i got: -5x +20

#28 (y^2 - y -1) + (y^2 + Y + 3)
i got: 2y ^2 + 2

#29 (x^2 + 1) - (2x^2 + x -1)
i got: -x^2 - x +2

# 27

- 5 x ( x - 4 ) =

- 5 x * x - 5 x * ( - 4 ) =

- 5 x ^ 2 + 20 x =

20 x - 5 x ^ 2

# 28

Correct

# 29

Correct