Question

If x is added to each of 14, 12, 34 and
30, the numbers so obtained, in this
order, are in proportion. What is the
value of 12x +9?​

Answer 1

Step-by-step explanation:

Given  

If x is added to each of 14, 12, 34 and 30, the numbers so obtained, in this order, are in proportion. What is the value of 12 x +9?

According to question we need to add x to each of the number. The numbers obtained will be in proportion.

So we have 14 + x : 12 + x : : 34 + x: 30 + x

14 + x / 12 + x = 34 + x / 30 + x

We know that by Componendo and Dividendo rule  

(a+b) / (a-b) = (c+d) / (c-d)

Similarly we can write this as

(14 + x) + (12 + x) / (14 + x) – (12 + x) = (34 + x) + (30 + x) / (34 + x) – (30 + x)

26 + 2x / 2 = 64 + 2x / 4

52 + 4x = 64 + 2x

2x = 64 – 52

2x = 12

Or x = 6

Now substituting x = 6 we get 12 x + 9

                                          = 12 (6) + 9

                                          = 72 + 9

                                           = 81

Reference link will be

https://brainly.in/question/11071639