(4k^2– 12) – (6k^2– 3k – 10)

What is the value of x in the this question ?

At the "no mutants allowed" country farm, every sheep has 4 legs, every chicken has two legs, and all animals have only 1 head. asked to count how many sheep and chicken are in the fields, a farm boy reports back that there are 140 feet and 50 heads. how many sheep and chicken are there? there are sheep and chicken at the farm.

Rationalize the denominator- 12x/√x-10