WAEC - Mathematics (2024 - No. 6)
If (3 - 4\(\sqrt{2}\))(1 + 3\(\sqrt{2}\)) = a + b\(\sqrt{2}\), find the value of b
-5
5
-21
21
Forklaring
(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