Geometry: Segment Addition Postulate please help!?

Question

Suppose J is between H and K. Solve for x, then find the length of each segment.

1) HJ=5x; JK=7x; KH=96

2) HJ=2x+5; JK=3x-7; KH=18

3) HJ=6x-5; JK=4x-6; KH=129

Answer 1

H ---- J --- K

   HJ    JK

HJ + JK = KH

1) 5x + 7x = 96

12x = 96

x = 8

HJ = 5x = 40

JK = 7x = 56

2) 2x+5 + 3x-7 = 18

5x -2 = 18

5x = 20

x=4

HJ = 2x+5 = 13

JK = 3x-7 = 5

3) plug and chug!