3d to the negative 4th times 4d to the fourth (simplify the expression)

Which triangle congruence postulate or theorem justifies my claim that the steps i made using construction paper and scissors produce an isosceles triangle? was it sss, sas, asa, aas, or hl?

Ineed me i stuck and i don’t want to get it wrong

Ineed to know the ordered pairs for this equation i need the answer quick because it’s a timed test