How did the theory of relativity change the law of conservation of energy? it stated that energy could be transformed into matter, therefore the amount of matter equals the amount of energy. it stated that matter could be transformed into energy, therefore the amount of matter equals the amount of energy. it stated that energy could be transformed into matter, therefore the amount of matter and amount of energy together are conserved. it stated that matter could be transformed into energy, therefore the amount of matter and amount of energy together are conserved.