Question

if a:b = b:d, prove that (9a+13b)(9c-13d) =(9c+13d)(9a-13b)​

Answer 1

Answer:

a/b = c/d

[Multiplying  both  sides  by 9/13]

9a/13b = 9c/13d

[By componendo  and dividendo]

9a + 13b/9a – 13b = 9c + 13d/9c – 13d

(By cross multiplication)

(9a + 13b)(9c – 13d) = (9a – 13b)(9c + 13d).

Hence  proved.

Step-by-step explanation:

Answer 2

if a:b = b:d, prove that (9a+13b)(9c-13d) =(9c+13d)(9a-13b)