Find the value of x2 - 7 if \(\sqrt {5x + 16}\) + \(\sqrt {5x - 16}\) = \(\sqrt {41}\) + \(\sqrt {9}\). |
15 18 32 35 |
18 |
We can easily see that x = 5 will satisfy the expression: ⇒ \(\sqrt {5x + 16}\) + \(\sqrt {5x - 16}\) = \(\sqrt {41}\) + \(\sqrt {9}\) ⇒ \(\sqrt {25 + 16}\) + \(\sqrt {25 - 16}\) = \(\sqrt {41}\) + \(\sqrt {9}\) ⇒ \(\sqrt {41}\) + \(\sqrt {9}\) = \(\sqrt {41}\) + \(\sqrt {9}\) Hence, x2 - 7 = 52 - 7 = 25 - 7 = 18 |