Help me please need a answer

How can we find the measure of an exterior angle if we know the measurement of an interior angle

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

Sundar used linear combination to solve the system of equations shown. he did so by multiplying the first equation by 5 and the second equation by another number to eliminate the y-terms. what number did sundar multiply the second equation by? 2x+9y=41 3x+5y=36