Atheorem can also be called a(n) a) conjecture. b) definition. c) postulate. d) proposition.

i think its D) proposition

Step-by-step explanation:

(D). Proposition

Step-by-step explanationA theorem is a proposition or statement that can be proven to be true every time. ... Just as a theory is an idea that can be supported or disproved, a theorem is also an idea, but it's one that has been proven and can be demonstrated again and again if used properly.

for ex: the reciprocal of 3/4 is 4/3. it is the opposite.

reciprocal definition:

a mathematical expression or function so related to another that their product is one; the quantity obtained by dividing the number one by a given quantity.

is should be y = 5x

step-by-step explanation:

correct me if im wrong