If (3 - 4\(\sqrt{2}\))(1 + 3\(\sqrt{2}\)) = a + b\(\sqrt{2}\), find the value of b
A
-5
B
5
C
-21
D
21
Verified Correct Answer: B.
Step-by-Step Mathematical Solution
(3 - 4\(\sqrt{2}\))(1 + 3\(\sqrt{2}\)) = a + b\(\sqrt{2}\),
3 + 9\(\sqrt{2} - 4\sqrt{2} - (4\sqrt{2} \times 3\sqrt{2}) = a + b\sqrt{2}\)
3 + 5\(\sqrt{2} - (4 \times 3\sqrt{2} \times \sqrt{2}) = a + b\sqrt{2}\)
3 + 5\(\sqrt{2} - (12 \times 2) = a + b\sqrt{2}\)
3 + 5\(\sqrt{2} - 24 = a + b\sqrt{2}\)
-21 + 5\(\sqrt{2}\) = a + b\(\sqrt{2}\)
Comparing both sides, we have b = 5
Source: Myschool Past Questions Archive (Record #71760)