Help me pzzz asap bc im being timed

Does the point (1, sqrt 7) lie on circle shown.

Analyze the solution below. 7 3 x = −2 7 3 x(3 7 ) = −2(3 7 ) x = − 6 7 what property was used to solve the equation? property of opposites division property of equality addition property of equality multiplication property of equality

∠a and ∠ b are complementary. if m∠ b = 80°, what is the measure of ∠ a? 10° 80° 90° 100°