H + K = 999 , K - H = 555 , 那麼 H = ( ? )

H + K = 999......(1)
K - H = 555
K = H + 555......(2)

Sub (2) into (1)

H + H + 555 = 999
2H = 444
H = 222

H=222

聯立分程：
{H+K=999.........(1)
{K-H=555..........(2)

(1).....K+H=999
(2).....K-H=555


(1)+(2)2K=1554
　　　　K=777

把K=777代入方程(1)，
777+H=999
H=222

H=222

這是和差問題:
H+K=999
K+H=999 ...1
K-H=555 ...2

1-2:
K-K+H-(-H)=999-555
H+H=444
2H=444
H=222, K=777

H + K = 999
soH=999- K
K - H = 555
K -(999- K)= 555
K -999+ K= 555
2K= 555+999
2K=1554
K=1554/2
K=777
那麼H= 999 -K
=999-777
=222

222!!!!!!!!!!!!!

h+k=999 k-h=555 k=777 h=222

H + K = 999---------(1)
K - H = 555
-H +K = 555------(2)
(1)-(2) 2H =444
H =222-----(3)
Sub into (1), 222 + K = 999
K = 777

222!!!!!!!!!!!!!

用2元1次聯立分程：
{H+K=999.........(1)
{K-H=555..........(2)
(1).....K+H=999
(2).....K-H=555
---------------------
(1)+(2)2K=1554
　　　　K=777
把K=777代入方程(1)，
777+H=999
H=222

999>H>555
H
H
H=222
K=777

H=222