Question

Calcule a temperatura na escala Celsius para que a correspondente indicação na escala Fahrenheit seja o dobro da indicação na escala Celsius.

Answer 1

°C/5= °F-32/9

°C/5= 2°C-32/9

9°C = 10°C-160
°C = 160°

Answer 2

$\tt 9tc\:=\:5\cdot \left(2tc\:-\:30\right)\\\\\\\tt 9tc=10ct-150\\\\\\\tt 9tc-10ct=10ct-150-10ct\\\\\\\tt -ct=-150\\\\\\\displaystyle \frac{-ct}{-t}=\frac{-150}{-t}\\\\\\\boxed{\tt C=150^\circ}$