Verified answer

That's not exactly true.

If we take y≥-1-2x, and multiply each side by -1, we would get

-y≤ 1+2x , since multiplying or dividing an inequality by a negative number changes the orientation of the inequality.

Your still doing the same thing to both sides of the inequality, like an equation. You just have to account for greater than/less than switch.

ex: 1<2, -1>-2

Just like for equalities you MUST do the same thing to both sides. So if it's true that

-y ≤ 1 - 2x

then

y ≥ 2x - 1