Find the value of x if O is between D & B and DO = 15, OB = 3x + 7, and DB = 9x - 2 x=

Sam claims that cos x =sin y if x and y are congruent angels. is sam correct ?

Parabolas y=−2x^2 and y=2x^2 +k intersect at points a and b that are in the third and the fourth quadrants respectively. find k if length of the segment ab is 5.

Anyone? 15m is what percent of 60m; 3m; 30m; 1.5 km?