Cao đẳng - Đại học
... 15914.x1− 2x2+3x 3 − 4x4=2,3x1+3x2− 5x 3 + x4= 3, −2x1+ x2+2x 3 − 3x4=5,3x1+3x 3 − 10x4=8.(DS. Hˆe.vˆo nghiˆe.m)15.x1+2x2+3x 3 − 2x4=1,2x1− ... 2x 3 − 3x4=2,3x1+2x2− x 3 +2x4= −5,2x1− 3x2+2x 3 + x4=11.(DS. x1=2 3 , x2= − 43 18, x 3 = 13 9, x4= −718)16.x1+2x2− 3x 3 +5x4=1,x1+3x2− ... nghiˆe.m)6.x1+2x2+3x 3 =14,3x1+2x2+ x 3 =10,x1+ x2+ x 3 =6,2x1+3x2− x 3 =5,x1+ x2 =3. (DS. x1=1,x2=2,x 3 =3) 7.x1+3x2− 2x 3 + x4+ x5=1,x1+3x2− x 3 +3x4+2x5 =3, x1+3x2−...