ax+b=cx+d
ax+b-cx=cx+d=cx
(a-c)x+b=d
(a-c)x+b-b=d-b
(a-c)x=d-b
x=(d-b)/(a-c)
ax+b=cx+d化成最简单的一元一次方程是 x=(d-b)/(a-c)