Question

please answer this question. number 16​

Answer 1

Answer:

Step-by-step explanation:

a / b = b / c

∴, b² = ac --------------- (i)

Now, (a + b + c)(a - b + c)

      = (a + c + b)(a + c - b)

Let a + c = x

      = (x + b)(x - b)

      = (x² - b²)                         [Using a² - b² = (a - b)(a + b)]

      = [(a + c)² - b²]                                                [x = a + c]  

      = (a² + c² + 2ac - b²)    [Using (a+b)² = (a² + b² + 2ab)]

      = (a² + c² + 2b² - b²)                                            [by (i)]

      = (a² + c² + b²)

      = a²  + b²  + c²