Ben and josh went to the roof of their 40-foot tall high school

Solve this system of equations. 12x − 18y = 27 4x − 6y = 10

Solve the triangle. a = 21°, c = 105°, c = 5

Which sum or difference identity would you use to verify that cos (180° - q) = -cos q? a.) sin (a -b) = sin a cos b – cos a sin b b.) cos (a -b) = cos a cos b – sin a sin b c.) cos (a -b) = cos a cosb + sin a sin b d.) sin (a + b) = sin a cos b + cos a sin b