Question

解三元一次方程:x+4y+3z=8,4x+y+2z=7,2x+2y-7z=-3

Answer 1

3y-16z

=2(2x+2y-7z)-(4x+y+2z)

=(-3)*2-7

=-13

15y+10z

=4(x+4y+3z)-(4x+y+2z)

=4*8-7

=25

根据3y-16z=-13

15y+10z=25

得,90z=(15y+10z)-5*(3y-16z)=25-5*(-13)=90

所以 z=1 y=1 x=1