Multiply (7–√) (−2–√) . Give an exact answer.(1 point)

Responses

14−−√
start root 14 end root

−14−−√
negative start root 14 end root

5–√
start root 5 end root

−72–√
negative 7 start root 2 end root

1 answer

To multiply \((7 - \sqrt{2})(-2 - \sqrt{2})\), we can use the distributive property (also known as the FOIL method for binomials):

\[ (7 - \sqrt{2})(-2 - \sqrt{2}) = 7 \cdot (-2) + 7 \cdot (-\sqrt{2}) - \sqrt{2} \cdot (-2) - \sqrt{2} \cdot (-\sqrt{2}) \]

Now calculate each term:

  1. \(7 \cdot (-2) = -14\)
  2. \(7 \cdot (-\sqrt{2}) = -7\sqrt{2}\)
  3. \(-\sqrt{2} \cdot (-2) = 2\sqrt{2}\)
  4. \(-\sqrt{2} \cdot (-\sqrt{2}) = 2\)

Now combine these results:

\[ -14 - 7\sqrt{2} + 2\sqrt{2} + 2 \]

Combine like terms:

The constant terms: \(-14 + 2 = -12\)

The terms with \(\sqrt{2}\): \(-7\sqrt{2} + 2\sqrt{2} = -5\sqrt{2}\)

Putting it all together, we have:

\[ -12 - 5\sqrt{2} \]

Thus, the exact answer is:

\(-12 - 5\sqrt{2}\) (not among the given options). If we are limited to the responses provided and need to match responses, the one that reflects a negative value would be the closest, but it does not accurately represent the computed answer. There might be an issue with the responses given, as none match.