Solve k^2+9+6k-x^2=

$$k ^ { 2 } + 9 + 6 k - x ^ { 2 } =$$

Factor

$$\left(-x-k-3\right)\left(x-k-3\right)$$

Solution Steps

Rewrite k^{2}+9+6k-x^{2} as \left(3+k\right)^{2}-x^{2}. The difference of squares can be factored using the rule: a^{2}-b^{2}=\left(a-b\right)\left(a+b\right).

$$\left(3+k-x\right)\left(3+k+x\right)$$

Reorder the terms.

$$\left(-x+k+3\right)\left(x+k+3\right)$$

Evaluate

$$\left(k+3\right)^{2}-x^{2}$$