C²-15

It seems like you have an expression \( C^2 - 15 \). If you're looking to factor this expression, it can be expressed in terms of a difference of squares if you write it in this form:

\[ C^2 - 15 = C^2 - (\sqrt{15})^2 \]

Using the difference of squares factoring formula \( a^2 - b^2 = (a - b)(a + b) \), we can write:

\[ C^2 - 15 = (C - \sqrt{15})(C + \sqrt{15}) \]

If you need help with further calculations or a different topic, feel free to ask!