The answer is 9(3+x)
My work is in the attached image
I don’t think I know but have a good day
So.. notice the picture below
and thus, we also know, that A = 51, thus

now, the height is just a value, it can't be negative, thus we can rule out -17, thus h = 6
and surely you'd know what the base is
Answer:
Solving the equation
by putting a=6, b=4 and d=1/2 we get 
Step-by-step explanation:
We are given formula: 
and values a=6, b=4 and d=1/2
We need to put the values of a, b and d in the given equation
and find their result
Putting values in the equation:

So, solving the equation
by putting a=6, b=4 and d=1/2 we get 
Answer: x=0 or x=−8/5
Step-by-step explanation: