Solve (u^2+3u

$$( u ^ { 2 } + 3 u$$

Factor

$$u\left(u+3\right)$$

Solution Steps

Factor out u.

$$u\left(u+3\right)$$

Steps Using the Quadratic Formula

Quadratic polynomial can be factored using the transformation ax^{2}+bx+c=a\left(x-x_{1}\right)\left(x-x_{2}\right), where x_{1} and x_{2} are the solutions of the quadratic equation ax^{2}+bx+c=0.

$$u^{2}+3u=0$$

All equations of the form ax^{2}+bx+c=0 can be solved using the quadratic formula: \frac{-b±\sqrt{b^{2}-4ac}}{2a}. The quadratic formula gives two solutions, one when ± is addition and one when it is subtraction.

$$u=\frac{-3±\sqrt{3^{2}}}{2}$$

Take the square root of 3^{2}.

$$u=\frac{-3±3}{2}$$

Now solve the equation u=\frac{-3±3}{2} when ± is plus. Add -3 to 3.

$$u=\frac{0}{2}$$

Divide 0 by 2.

$$u=0$$

Now solve the equation u=\frac{-3±3}{2} when ± is minus. Subtract 3 from -3.

$$u=-\frac{6}{2}$$

Divide -6 by 2.

$$u=-3$$

Factor the original expression using ax^{2}+bx+c=a\left(x-x_{1}\right)\left(x-x_{2}\right). Substitute 0 for x_{1} and -3 for x_{2}.

$$u^{2}+3u=u\left(u-\left(-3\right)\right)$$

Simplify all the expressions of the form p-\left(-q\right) to p+q.

$$u^{2}+3u=u\left(u+3\right)$$

Evaluate

$$u\left(u+3\right)$$