To find which of the following are equal to -40 degrees F, we need to convert the other temperatures to degrees Fahrenheit and compare them.

1) -40°C:

To convert from Celsius to Fahrenheit, we use the formula: °F = (°C × 9/5) + 32

-40°C = (-40 × 9/5) + 32

-40°C = (-360/5) + 32

-40°C = -72 + 32

-40°C = -40°F

So, -40°C is equal to -40°F.

2) 120°K:

To convert from Kelvin to Fahrenheit, we use the formula: °F = (°K × 9/5) - 459.67

120°K = (120 × 9/5) - 459.67

120°K = (1080/5) - 459.67

120°K = 216 - 459.67

120°K = -243.67°F

So, 120°K is not equal to -40°F.

3) -60°C:

-60°C = (-60 × 9/5) + 32

-60°C = (-540/5) + 32

-60°C = -108 + 32

-60°C = -76°F

So, -60°C is not equal to -40°F.

Therefore, the only temperature that is equal to -40°F is -40°C.