Question

It would be nice if I get some help with these 2 things

Answer 1

Thing 1
A. You can set up a proportion by dividing how much of something there is by the original. (This probably doesn't make much sense but I hope you can understand it from the answer to the problem below!)
B.First, do 168/21 to see how many more times he put flour in. 
168/21= 8
Then to find out the milk in the same proportion do the number (in this case 8) times the original of the thing you wan to find out. 
8x9=72
72 tablespoons of milk are needed for 168 cups of flour in this adapted recipe.

Thing 2
24/36=8y
To solve any equation, you want to have letters on one side and numbers on the other, so...
-8 from both sides...
(24/36)-8=y
24/36=0.6 
y=(0.6-8)
y=-7.4

Hope this helps :)