Water freezes at 0 degrees Celsius. 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?

-7°C

Step-by-step explanation:

Freezing point of water = 0°C

By adding salt, freezing point lowers by 7°C ;

The freezing point of salt water can be expressed as ;

Since temperature lowers :

Freezing point of salt water :

Freezing point of water - 7°C

0°C - 7°C

= - 7°C

-1   1/6.   you dont subtract the denominators

step-by-step explanation:

step-by-step explanation:

we have

using a graphing tool

see the attached figure

this is a quadratic equation (vertical parabola) open up

the vertex is a > vertex

the domain of the function is all real > interval (-∞,∞)

the range of the function is the > [-6.125,∞)

the function has two x->   and

the function is increasing over the > (0.25,∞)

the function is decreasing over the > (-∞,0.25)