When the slope is zero, the line is horizontal. Its equation will be of the form
... y = constant
The y-value of your point is specified as -9, so the equation of the line through that point is
... y = -9
All you have to is divide two consecutive terms to calculate the common ratio
1/4 divided by 5/12 = 1/4 * 12/5 = 12/20 = 3/5
add all assets then add all liabilities
if assets is higher she has a positive net worth of the difference
if liabilities is higher she has a negative net worth of the difference