\[ k) x^{2}-3 x=0 \] i) $5 x^{2}+80 x=0$ ta) $3 x^{2}-6 x=0$

Step 1 ：Factor each equation and solve for x.

Step 2 ：For equation k) \(x^2 - 3x = 0\), the solutions are \(x = 0\) and \(x = 3\).

Step 3 ：For equation i) \(5x^2 + 80x = 0\), the solutions are \(x = -16\) and \(x = 0\).

Step 4 ：For equation ta) \(3x^2 - 6x = 0\), the solutions are \(x = 0\) and \(x = 2\).

Step 5 ：\(\boxed{\text{k) } x = 0, 3; \text{ i) } x = -16, 0; \text{ ta) } x = 0, 2}\)