Solve a^2+2a

$$a ^ { 2 } + 2 a$$

Factor

$$a\left(a+2\right)$$

Solution Steps

Factor out a.

$$a\left(a+2\right)$$

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.

$$a^{2}+2a=0$$

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.

$$a=\frac{-2±\sqrt{2^{2}}}{2}$$

Take the square root of 2^{2}.

$$a=\frac{-2±2}{2}$$

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

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

Divide 0 by 2.

$$a=0$$

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

$$a=-\frac{4}{2}$$

Divide -4 by 2.

$$a=-2$$

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 -2 for x_{2}.

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

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

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

Evaluate

$$a\left(a+2\right)$$