I I i ι

Solve[{2x+3i y==4, 5x-7y==5},{x,y}]

(1+I)/(2-3I)

Solve[{2x+3I y==4, 5x-7y==5},{x,y}]

Solve[{2x+3I y==4, 5x-7y==5},{x,y}]

4-2I == 4-2*I

Solve[{2x+3y==1,2x+3y==0},{x,y}]

eqn1 = 5a-3b+6c+8d==1;
eqn2 = 9a+4b-17c+2d==20;

Solve[{eqn1,eqn2},{a,b,c,d}]

Solve[{eqn1,eqn2},{a,c}]

EQNS  = {{5,-3,6,8,1},{9,4,-17,2,20}}

EQNS//MatrixForm

RowReduce[EQNS]//MatrixForm

Solve[{eqn1,eqn2},{a,b}]

eqn3 = 7a-2b-3c+d==29;

Solve[{eqn1,eqn2,eqn3},{a,b,c,d}]

EQNS//MatrixForm

(EQNS2 = Join[EQNS,{{7,-2,-3,1,29}}])//MatrixForm

RowReduce[EQNS2]//MatrixForm

Solve[{eqn1,eqn2,eqn3},{a,b,c}]

EQNS2//MatrixForm

EQNS2a = {{-3,6,8,5,1},{4,-17,2,9,20},{-2,-3,1,7,29}}

EQNS2a//MatrixForm

RowReduce[EQNS2a]//MatrixForm

Solve[{eqn1,eqn2,eqn3},{b,c,d}]

Expand[%]

eqn4 = 5a-2b+4c+d==15;

Solve[{eqn1,eqn2,eqn3,eqn4},{a,b,c,d}]

(EQNS3 = Join[EQNS,{{7,-2,-3,1,29},{5,-2,4,1,15}}])//MatrixForm

RowReduce[EQNS3]//MatrixForm

RowReduce[{{1,2,3,-1},{4,5,-6,7},{5,7,-3,5}}]//MatrixForm

(A = {{2,4,5},{-1,2,1},{4,5,0}})//MatrixForm

(B = {{2,3},{-1,4},{4,4},{0,1}})//MatrixForm

(Cm = {{3,2,-1,0},{-5,2,3,0},{0,2,4,-1},{5,5,-1,-1}})//MatrixForm

(Dm = {{3,-1,0},{2,3,0},{0,2,4},{5,-1,-1}})//MatrixForm

272*A//MatrixForm

Cm.B//MatrixForm

Cm[[1,1]]*B[[1,1]]+Cm[[1,2]]*B[[2,1]]+Cm[[1,3]]*B[[3,1]]+Cm[[1,4]]*B[[4,1]]

Sum[Cm[[1,k]]*B[[k,1]],{k,1,4}]

Sum[Cm[[3,k]]*B[[k,2]],{k,1,4}]

Sum[Cm[[4,k]]*B[[k,1]],{k,1,4}]

Cm//MatrixForm

(Cm+Cm)//MatrixForm

(3Cm+Cm)//MatrixForm

Cm.Cm//MatrixForm

Cm^2//MatrixForm

MatrixPower[Cm,2]//MatrixForm

Dm.A.A.A//MatrixForm

Cm.B//MatrixForm

B.Cm

A = {{1,3},{-2,1}};
B = {{5,-3},{2,7}};

A-2B