Solving Congruent Complements

∠B is complementary to ∠D and ∠D is complementary to ∠F. If m∠B = (10x - 15)⁰ and m∠F. = (7x - 6)⁰, what is m∠B?

∠B is complementary to ∠D and ∠D is complementary to ∠F. If m∠B = (3x - 4)⁰ and m∠F. = (2x+4)⁰, what is m∠B?