Help me with this pls

Valentina is subtracting from . she finds the lcd to be 15y2. what is valentina's next step?

The trigonometric ratios sine and secant are reciprocals of each other

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