Solve each equation:

(x^2-3)(x^2+3x-4)=0
(x+2/3)(x^2+5x+1)=0
x^3-2x^2+x=0
x^3+3x^2-5x-4=0

Some are already factored. Some are partially factored. Set the factors equal to zero.

Example:
x^3 -2x^2 +x = 0
x(x^2 -2x +1) = 0
x(x-1)^2 = 0
x = 0 or 1.

The last cubic equation will be harder to factor. Hint: One solution is x = -4, so x+4 is a factor.
Use polynomial long division to get the quadratic factor, and then use the quadratic equation for the other two roots.