Honestly this problem you can use both x and y but x tends to be the easier one to use and i would use the first equation because it is easier to solve because all the numbers are even.<span />
C(25,10)= 3268760
P(25,10)=11861676288000
hope it helps but these are very big numbers :d
The coefficient in (2/3q-3/4) is 2/3 and in (-1/6q-r) is -1/6
(x + 1)·(x + 1 + 11) = (x + 4)·(x + 4 + 1) --> x = 2
Tools like "photomath" are able to help you solving such equations.
