Pls me algebraic expression 1."the sum of a number and sixteen"2.the difference of a number and eight"3."the quotient of a number and twelve"

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