So use undistributive properyt]
ab+ac=a(b+c)
so factor 24a dadn 28 to find 'a' the common factor
24=2 times 2 times 2 times 3 tiems a
28=2 times 2 times 7
common one is 2 itmes 2=4
a=4
4(2 times3 times a)+4(7)=4(6a)+4(7)=4(6a+7)
1. m∠1 + m∠2 = 180°
2. Definition of bisector
3. m∠1 + m∠3 = 180°
4. Substitution Property of Equality