The perimeter of a triangle is 91 centimeters if two sides are equally long and the third side is 7 centimeters longer than others find the lengths of the three sides

Could somebody me with this radical simplification?

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

Compound inequalities. , i’m being timed