What Celsius temperature will the Fahrenheit thermometer be 4-times more than on the Celsius thermometer?

Question

At what Celsius temperature will the numerical reading on the Fahrenheit thermometer be 1/9 that on the Celsius thermometer?

Answer 1

I just need a solution to the first half of the question I figured out the 2nd half

Answer 2

(9/5)c + 32 = 4c
Solve for c.

Answer 3

thank you