Introduction 1.Linear Equation: a1x1+·…+amxn=b. 2.a simple systems of linear equations: a1十12x十-十41nw=b 2x1+x2+十y=b dm1十d2十十du=bn Tongji University】 2/32Introduction 1. Linear Equation: a1x1 + · · · + anxn = b. 2. a simple systems of linear equations：    a11x1 + a12x2 + · · · + a1nxn = b1 a21x1 + a22x2 + · · · + a2nxn = b2 . . . . . . am1x1 + am2x2 + · · · + amnxn = bm (Tongji University) Linear Algebra 2 / 32