PLS HELP I WILL GIVE BRAINLIIEST Which equation results from adding the equations in this system?

x + 6 y = 9. -x + 2 y = -15.

A) 8 y = negative 6
B) 8 y = 6
C) 4 y = 24
D) 4 y = negative 6

With these 5 geometry questions! pls 1.)quadrilateral abcd is inscribed in this circle. what is the measure of ∠a ? enter your answer in the box.°2.)quadrilateral abcd is inscribed in a circle. what is the measure of angle a? enter your answer in the box. m∠a= 3.)quadrilateral abcd is inscribed in this circle. what is the measure of angle b? enter your answer in the box. m∠b= °4.)quadrilateral abcd is inscribed in this circle. what is the measure of angle a? enter your answer in the box.°5.) quadrilateral abcd is inscribed in this circle. what is the measure of angle c? enter your answer in the box.°