There's no equation to solve, until you tell us
what that expression is equal to.
That's a trapezoid,


Answer: 32
But say we didn't know the formula. We can chop out the 4 by 4 square and we have two 45/45/90 triangles side 4 left over, so two 4 by 4 squares,
A = 2(4)(4) = 32
We can think of this as 12 by 4 rectangle with two 4 by 4 right triangles chopped out:
A = 12(4) - 2(1/2)(4)(4) = 48 - 16 = 32
Answer:
The principal amount was $23,393.45
Step-by-step explanation:
The total amount paid on a 35 year loan was $98,000 at the rate of interest 4.1%
We will calculate Principal amount by this formula

Where A = amount (98,000)
P = Principal amount (P)
r = rate of interest 4.1% (0.041)
n = number of compounding interest monthly (12)
t = time (35 years)



98,000 = P(4.189386)
= 4.189386P = 98,000
P = 
P = 23,392.4494 ≈ $23,392.45
The principal amount was $23,393.45
We would need to know how many are in each box to figure this out.