How do you calculate when degrees Fahrenheit equal degrees Celsius?

Answer 1

Take one of the formulas you use to convert one to the other.

Let's say, take the formula used to convert °C to °F :

F = 1.8 C + 32.

Since we want the °F and °C numbers to be equal, we can replace

the 'F' on the left side with 'C':

C = 1.8 C + 32

Subtract 32 from each side:

C - 32 = 1.8 C

Subtract C from each side:

-32 = 0.8 C

Divide each side by 0.8 :

-32/0.8 = C = -40

That's the number to remember:

-40°F = -40°C

Answer 2

-40

T (0F) = 32+1.8 *T(0C)

T(0F)=T(0C)=X

X=32+1.8*X

-0.8X=32

X=32/-0.8

X=-40

Answer 3

At -40o.