Solve k^2+7k

$$k ^ { 2 } + 7 k$$

Factor

$$k\left(k+7\right)$$

Solution Steps

Factor out k.

$$k\left(k+7\right)$$

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.

$$k^{2}+7k=0$$

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.

$$k=\frac{-7±\sqrt{7^{2}}}{2}$$

Take the square root of 7^{2}.

$$k=\frac{-7±7}{2}$$

Now solve the equation k=\frac{-7±7}{2} when ± is plus. Add -7 to 7.

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

Divide 0 by 2.

$$k=0$$

Now solve the equation k=\frac{-7±7}{2} when ± is minus. Subtract 7 from -7.

$$k=-\frac{14}{2}$$

Divide -14 by 2.

$$k=-7$$

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 -7 for x_{2}.

$$k^{2}+7k=k\left(k-\left(-7\right)\right)$$

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

$$k^{2}+7k=k\left(k+7\right)$$

Evaluate

$$k\left(k+7\right)$$