What does it mean when the resulting temperature is above 0 on the number line? What does it mean when a temperature is below 0?

It means that above 0 degrees Celsius the water does not freeze, whereas 0 degrees are freezing teperatures of water.

Step-by-step explanation:

Water freezes at 0 degrees Celsius, but the freezing temperature can be lowered  by adding salt to the water. A student discovered that adding half a cup of salt to  a gallon of water lowers its freezing temperature by 7 degrees Celsius. What is  the freezing temperature of the gallon of salt water?

0° - 7° = -7°

2/3x + 7 = 29

step-by-step explanation:

two thirds = 2/3

plus a number = x

at least 29 = 29

there for you should get 2/3x + 7 = 29