Respuesta :

Answer:

x=9

Step-by-step explanation:

[tex] \frac{9}{72} = \frac{3x - 20}{56} [/tex]

Cross multiply

[tex]504 = 216x - 1440[/tex]

Transfer and isolate

[tex] \frac{504 + 1440 = 216x}{216} [/tex]

[tex] \frac{1944 = 216x}{216} [/tex]

[tex]9 = x[/tex]

Answer:

9 cm

Step-by-step explanation:

9/(9+72) = (3x-20)/(3x-20+56)

9/81 = (3x-20)/(3x+36)

1/9 = (3x-20)/(3x+36)

3x + 36 = 27x - 180

24x = 216

x = 9cm