Find ab if bc = 4 , bd = 5, and ad =4

Which of the following is an equation of a line parallel to the equation y=4x+1?

If cos(2x) = tan^2(y), show that cos(2y) = tan^2(x).

50 plz, given the system of equations, match the following items. x + 3 y = 5 x - 3 y = -1 a) x-determinant b) y-determinant c) system determinant match the following to the pictures below.