In Problems 49-58 find a homogeneous linear differential equation with constant coefficients whose general solution is given.
49. y = c₁e + c2e5x
50. y c1e-4x + c2e-3x = ce
51. y = c + c2e2x
52. y = cie 10x + C2Xe10x
53. y c₁ cos 3x + c2 sin 3x
54. y c₁ cosh 7x + c2 sinh 7x
55. y ce cosx + c2e sinx