a11x1+a12x2=b1a21x1+a22x2=b2用些方程组如和才能解得以下方程组：（a11a22–a12a21）x1=b1a22–b2a12（a11a22–a12a21）x2=b1a11–b2a21注：数字都是在字母右下角的.

Question

a11 x1+ a12 x2 = b1
a21 x1+ a22 x2 = b2
用些方程组如和才能解得以下方程组：
（a11 a22 – a12 a21）x1= b1 a22 – b2 a12
（a11 a22 – a12 a21）x2= b1 a11 – b2 a21
注：数字都是在字母右下角的.

Answer 1

a11 x1+ a12 x2 = b1 ①
a21 x1+ a22 x2 = b2 ②
①xa22-②xa12即得（a11 a22 – a12 a21）x1= b1 a22 – b2 a12
①xa11-②xa21即得（a11 a22 – a12 a21）x2= b1 a11 – b2 a21.