To factor out the coefficient of a variable you divide it by the sum.
Answer:
C. 
Step-by-step explanation:
You can use the formula to find the slope: 
(-1.5, 1.5) & (1.5, 0)

The slope is 
You could use the equation
+4+(-4)=0 if:
-you earn $4 and spend it
-buying 4 candy bars then eating them
-earning 4 points then losing them
Divide the denominator by the numerator