Answer:
For the first equation we have:
A*x = b
solving for x, we get:
x = b/A
If it always has a solution, then we can not have A = 0, because that causes an undefined operation.
so for example, if we have A = 1 and b = 2
x = b/A = 2/1
For the other case,
A*y = 0
dividing both sides by A
y = 0/A = 0
y = 0
Here we have only one possible solution, the trivial one, y = 0.
And the dependence on A disappears (because the quotient between zero and a number different than zero is always zero)
