Can you check these problems?

Question

1. 4x^2 + 3x - 4x +5
= 4x^2 - x + 5

2. m - n + m - n - n
= 2m - 3n

3. (7x + 5 - 3y) - (-3x - 5 +4y)
= 7x + 3x -3y + 4y + 0
= 10x - y = 0

4. m/8 - 9 = 5
m/8 = 5 + 9
m = 14/8
m = 7/4 = 1 3/4

Answer 1

For #4 should be:
m/8 = 5 +9
m/8 = 14
m = 14*8
m = 112/8

Answer 2

sorry, typo on #4 still. answer is just 112

Answer 3

For the 3rd should be:

=7x + 5 - 3y + 3x + 5 - 4y
=10x -7y + 10

Answer 4

Thanks!!