The set of multiples of 8 which are greater than 20 but less than 40

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

Ineed on this question me get the answer

Solve -3 (r + 5) = -9 enter ur answer in the box x = __