Question

-4 squareroot 63 + 9 squareroot 7

Answer 1

To simplify the expression \(-4\sqrt{63} + 9\sqrt{7}\), we first simplify \(\sqrt{63}\).

\[
\sqrt{63} = \sqrt{9 \cdot 7} = \sqrt{9} \cdot \sqrt{7} = 3\sqrt{7}
\]

Now, we can substitute \(\sqrt{63}\) in the original expression:

\[
-4\sqrt{63} + 9\sqrt{7} = -4(3\sqrt{7}) + 9\sqrt{7}
\]

This simplifies to:

\[
-12\sqrt{7} + 9\sqrt{7}
\]

Now, we can combine the terms:

\[
(-12 + 9)\sqrt{7} = -3\sqrt{7}
\]

Thus, the final simplified expression is:

\[
\boxed{-3\sqrt{7}}
\]