It is certainly possible for a function decreasing over a certain interval to be negative, but no rule that says it must be. On the other hand, where the function is decreasing, the rate of change of the function must be negative.
I got 42.5 cuz 4x+10=180 then take away 10 from both sides so 4x=170 and you divide each side by 4
Given :
Rain is falling at 0.5 inches per hour and 1.5 inches have already accumulated.
To Find :
How many hours must have passed if there are 5 inches of rain .
Solution :
Let , after x hours rain accumulated is 5 inches .
We know , general equation of line :
y = mx +c
Here , m = 0.5 and c = 1 .
So , equation of rain accumulated is :

Now , putting value of x = 5 hours .
We get :

Hence , this is the required solution .
Distribute the negative:
6x-3-8x-11
Combine like terms:
-2x-14
Simplify by factoring:
-2(x+7)
N= -7; open the first bracket, then add the two negatives.Then open the second bracket, and cancel opposite sign 3's and then solve.