MCQ
Which of the following is the value $(\sqrt{11}-\sqrt{7})(\sqrt{11}+\sqrt{7})?$
- A$\sqrt{7}$
- B$\sqrt{11}$
- C-4
- D4
✓
Answer
- 4
Solution:
$(\sqrt{11}-\sqrt{7})(\sqrt{11}+\sqrt{7})$
$=(\sqrt{11})^2-(\sqrt{7})^2$
$=11-7$
$=4$
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