Respuesta :

Answer:

15

Step-by-step explanation:

To solve this, divide 192 by 8:

192/9 = 24

Subtract 9 from 24:

24 - 9 = 15

Therefore, 8 times the sum of 9 and 15 is 192

8 times(9+x)= 192 where x= “that” certain number.
Multiplying the left side through by 8 gives

72+8x=192
8x= 192-72
8x= 120
Since were finding 8, 8 divides the 120 giving 15
Hence, x(that certain number) = 15.