Why the results of the matrix X' dont show?

I'm just trying to prove if x4 = 0 the matrix X' will be [100+0 -400+0 -500+0 0], but i only recive red flags :(, someone know what i did wrong to fix it ?

A = [0 2 -1 0 ; 0 0 1 -1 ; 1 -1 0 0 ; -1 0 0 1]

B= [100 -500 300 100]

X = inv(A)*B

for x4 = 0:1:100

X' =[-100+x4 -400+x4 -500+x4 x4]

if X'=X

break

end

end

[Stephen23]

A = [0,2,-1,0;0,0,1,-1;1,-1,0,0;-1,0,0,1];
B = [100;-500;300;100];
X = A\B % more robust than INV(A)*B

X = 4×1

300 0 -100 400

Why do you expect X to be [100;-400;-500;0] ?

[Ian Samuelsson]

because i'm trying to prove the values when x4=0, in the question they want to know the values of the matrix when x4=0 (is a trafic application, if the street x4 flow is zero, how this will afect the matrix).

i think that i exaggerated the arguments and got confused, thank you !

[Ian Samuelsson]

put your answer in answer this question plz, soo can i give your tag

Answer 1

[Stephen23]

Use https://www.mathworks.com/help/matlab/ref/mldivide.html

A = [0,2,-1,0;0,0,1,-1;1,-1,0,0;-1,0,0,1];
B = [100;-500;300;100];
X = A\B % more robust than INV(A)*B

X = 4×1

300 0 -100 400