Write the negative exponents in the denominator. Then get a common denominator for both your derivatives. It will simplify your equations drastically.
i have to find stationary values of: f(x,y) = xy^0.5(10-x-y)^0.4
f1=> y^0.5*(10-x-y)^0.4-0.4*x*y^0.5(10-x-y)^-0.6= 0 (function differentiated with respect to x)
f2=> 0.5*x*y^-0.5*(10-x-y)^0.4-0.4*x*y^0.5*(10-x-y)^-0.6= 0 (function differentiated with respect to y)
(Solving both for 0 should get me the stationary values.)
so now i get a system of 2 (differential)equiations but no matter how hard i try, i cant seem to solve it. Please help me out.