What is slop of the line that passes through the ponitss (5, -4) and (7, -4)

Can someone me with my hwplz(only the circled ones)

What is the value of x in the this question ?

In the field of thermodynamics, rankine is the unit used to measure temperature. one can convert temperature from celsius into rankine using the formula , what is the temperature in celsius corresponding to r degrees rankine? a. 9/5(c - 273) b. 9/5(c + 273) c. 5/9( c - 273) d. 5/9( c + 273)