CRT - non-linear system of equations

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I don't know how to solve system of equations using CRT when there is some quadratic/cubic variable. For example:

System 1: $$\boxed{x^3 \equiv 1 \pmod{3}}$$ $$12x \equiv 9 \pmod{15}$$

System 2: $$3x \equiv 6 \pmod{9}$$ $$\boxed{x^2 \equiv 1 \pmod{4}}$$ $$4x \equiv 2 \pmod{5}$$

I think (please correct me if I'm wrong) the quadratic equation from System 2 can be rewritten into linear equations as $x \equiv \pm 1 \pmod{2}$.

How can I rewrite the cubic equation from System 1 into linear equations to be able to use CRT?

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Every number is congruent to either 0,1 or 2 mod 3. The only option which cubes to 1 mod 3 is 1. Therefore x must be 1 mod 3