Question

The formula F = 1.8C + 32 gives the temperature in degrees Fahrenheit (F) for a given temperature in degrees Celsius (C). There is one temperature for which the number of degrees Fahrenheit is equal to the number of degrees Celsius. Complete the equation you can solve to find that temperature and then use it to find the temperature. Use the variable C to represent the number of degrees Celsius where degrees Fahrenheit and degrees Celsius are the same. The equation is . The temperature for which the number of degrees Fahrenheit is equal to the number of degrees Celsius is °C.

Answer 1

-40 °F = -40 °C

Explanation:

(1) F = 1.8 C + 32

If the Fahrenheit and Celsius temperatures are the same, then

(2) F = C Substitute (2) into (1)

C = 1.8C + 32 Subtract 1.8 C from each side

C – 1.8 C = 32 Combine like terms

-0.8C = 32 Divide each side by -0.8

C = -32/0.8

(3) C = -40 Substitute (3) into (1)

F = 1.8(-40) + 32

F = -72 + 32

F = -40

So, -40 °F = -40 °C

The thermometer below shows that -40 °F = -40 °C.