How can I operate a matrix by a vector?

Hi, I need nelp.

I need to perform the following function f (x) = || Ax - b || ^ 2

A = [2 3, 1-2, 4 1];

b = [2,4, -5];

syms x1 x2

x = [x1 x2];

(sqrt ((A * x-b) ^ 2)) ^ 2

Answer 1

[KSSV]

A = [2 3 ; 1 -2 ; 4 1];
b = [2,4, -5]';
syms x1 x2
x = [x1 ; x2];
f = (sqrt ((A * x-b) .^ 2)) .^ 2

f =