Introduction 1.Linear Equation: a1x1+·…+amxn=b. 2.a simple systems of linear equations: a11x1+a12x2+··+a41mxm=b1 a21x1+a22x2+··+a2n-xn=b2 am1x1+am2X2十··+AmnXn=bm 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