Ineed to know how much is 3\4x8.( sorry for my bad grammar)

Which of these is and example of a literal equation? a) 6+30=6^2 b)3x-4y c)12=9+3x d)ax-by=k

At 6 1/2 cents per pound of string beans how much does 7 pounds cost

Rhombus adef is inscribed into a triangle abc so that they share angle a and the vertex e lies on the side bc . what is the length of the side of the rhombus if ab=c, and ac=b.