Why least square problem always has solution for arbitrary b?
112428
Existence of least squares solution to $Ax=b$
76175
Does the equation have a real solution...please help!
74452
On a uniqueness proof for solutions of $\ a + x = b\,$ in a group
25296
Difference between least squares and minimum norm solution
126261
Extraneous solution from substituting in equations
87387
Linear equations given by $Ax = b$ have a solution if and only if $\operatorname{rank}(A|b) = \operatorname{rank}(A)$
20900
Regression without intercept: deriving $\hat{\beta}_1$ in least squares (no matrices)
110408
Solving for $A$ in $Ax = b$
66913
Why does the maximum/minimum of linear programming occurs at a vertex?
158534
Proof that any linear system cannot have exactly 2 solutions.
17265
Intuition for why equations of the form $k^x=x^c$ are not solvable trivially?
62868
Birthday Problem: Difference between Canonical Solution and Approximation
152451
REVISITED $^2$: Does a solution in $\mathbb{R}^n$ imply a solution in $\mathbb{Q}^n$?
144841
Find general solution $y''y^3=1$
121237
Solving $x - a \log(x)=b$
123808
How would I solve the following problem involving elementary matrices?
49453
Why do I have to solve for $x$ in this proof, if I choose not to find a counterexample?