Question

(x-9):(3x+6) is the duplicate ratio of 4:9 find x.

Answer 1

(x-9):(3x+6) = 4:9
=> (x-9)/(3x+6) = 4/9
=> 9(x-9) = 4(3x+6)

=> 9x-81 = 12x+24
=> 9x-12x = 24+81 => 105

=> -3x = 105
=> -x = 105/3 => 35
=> x = -35

hope this helps

Answer 2

(x-9):(3x+6) = 4:9
(x-9)/(3x+6) = 4/9
 9(x-9) = 4(3x+6)
 9x-81 = 12x+24
9x-12x = 24+81 =105

-3x = 105
-x = 105/3 =35
 x = -35

So, -35 is the answer.