Math problem. D: help please

K, I don't get this problem 7 - 5u = -43, please help (It can't be a decimal or fraction) and if possible can you help me on these too? 14 + 4x = 38 and -40 = 8 - 6s

Add 43 to both sides to get 50 - 5u = 0.
Add 5u to both sides to get 50 = 5u
Divide both sides by 5 to get 10 = u.

Subtract 14 from both sides to get 4x = 24
Divide both sides by 4 to get x = 6

You now do the last one.

7-5u=-43
-7 -7
--------------
-5u=-50
----- -----
-5 -5
_______
u= 10

14+4x=38
-14 -14
---------------
4x= 24
--- -----
4 4
_______
x= 6
-40=8-6s
-8 -8
-------------
-48=-6s
----- ----
-6 -6
_______
8=s

subtract 7 from both sides you get: 5u=-50 . 5X-10= 50 so U=-10