數學,a和b的長度是整數.1/3 a等於 1/4 b.而b比a長23厘米,求a的長度

1/3 a = 1/4 b
a = 3/4 b ----(1)

b - a = 23----(2)

put (1) into (2)
b - 3/4 b = 23
1/4 b = 23
b= 92

so a = 92 x 3/4
= 69

1/3 a等於 1/4 b 得 1/3a=1/4b 即 4a=3b
而b比a長23厘米 得 b=a+23cm
把 b=a+23cm 左右乘以3 得 3b=3a+69cm
因4a=3b，所以代入得 4a=3a+69cm 即 a=69, b=92