The question is in the picture above^^

Given the two similar triangles, how do i find the missing length? if a=4, b=5, and b'=7.5 find a'

The value of the expression 16-^3/4 8 1/8 -6 6 1/40 1/64

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