If k is the midpoint of hj and hk =x+6 and hj =4x-6 then what does kj equal

Given: k= midpoint
hk=x+6
hj=4x-6

Remember midpoint cuts the segment hj in equal parts that means hk=kj and hk+kj=hj
hk+hk=hj
2hk=hj

2hk=hj
2 (x+6)=(4x-6)
2x+12=4x-6
2x-2x+12=4x-2x-6
12=2x-6
12+6=2x-6+6
18=2x
18/2=2x/2
9=x

hk=kj=x+6=(9)+6=15
kj=15

Cis your correct answer