4x+12−12=4−12 what step is this

If cos(2x) = tan^2(y), show that cos(2y) = tan^2(x).

The function show two sisters' savings account and the rate at which they plan to deposit money

In the figure below, segment ac is congruent to segment ab: which statement is used to prove that angle abd is congruent to angle acd? a.)triangle acd is similar to triangle abd. b.)triangle acd is congruent to triangle abd. c.)segment a.d. is congruent to segment ac. d.)segment a.d. is congruent to segment dc.