Multiply, and then simplify if possible. Assume all variables represent positive real numbers.
-$( \sqrt { 7 } + 5 ) ( \sqrt { 7 } - 5 )$
A) $- 18$
B) 2
C) $7 - 2 \sqrt { 5 }$
D) 32

Question

Quizplus · Accepted Answer

This is an application of the difference of squares formula, $a^2 - b^2 = (a + b)(a - b)$. Here, $a = \sqrt{7}$ and $b = 5$, so the expression simplifies to $\sqrt{7}^2 - 5^2 = 7 - 25 = -18$.

Multiply, and Then Simplify If Possible (7+5)(7−5)( \sqrt { 7 } + 5 ) ( \sqrt { 7 } - 5 )(7​+5)(7​−5)

Multiply, and Then Simplify If Possible $( \sqrt { 7 } + 5 ) ( \sqrt { 7 } - 5 )$