Question 1178014

D(BC )

Distance Equation Solution:
d=sqrt((2−12)2+(−7−(−2)))

d=sqrt((−10)2+(−5)

d=sqrt((100+25))

d(BC)=√125

d(AB) 

Distance Equation Solution:
d=sqrt((a−12)^2+(18−(−2)^2))

d=sqrt((a^2-24a+144 +400))

d=sqrt( a^2-24a+544)

AB = 2BC

sqrt( a^2-24a+544) =10sqrt(5)

a^2-24a +544 =100*5

a^2-24a+44=0

a^2-22a-2a+44=0

(a-2)(a-22)=0

a=2 Or 22

slope of BC

Slope =y2−y1/x2−x
 of AD


−7−−2/2−12

−5/−10

1/2= slope of BC = slope of AD

equation of AD 

use y = mx+c