What is 5/6 + 3/8 in the simplest form

The graph represents the gallons of water in a water tank with respect to the number of hours since it was completely filled

Ineed to know the answer to this algebra question.

Find the directions in which the function increases and decreases most rapidly at upper p 0p0. then find the derivatives of the function in these directions. f(x,y)equals=x squared plus xy plus y squaredx2+xy+y2, upper p 0p0left parenthesis 1 comma negative 4 right parenthesis