Answer:
![A=4x^5+16x^4+4x^3](https://img.qammunity.org/2021/formulas/mathematics/middle-school/nnwg16g6827zp7ppo5knwi5z36uz0jqjcn.png)
Explanation:
The area of a trapezoid is found with the formula
![A=((B+b)h)/(2)](https://img.qammunity.org/2021/formulas/mathematics/high-school/x5dovd7r97lyx6af7vjkyisyv0mkma9mio.png)
where B is the measurement of the longest side of the trapezoid (the largest base) and b is the measurement of the shortest side of the trapezium (the minor base), and h is the height. In this case we have:
![b=8x^2+3x\\B=2x^3-x\\h=4x^2](https://img.qammunity.org/2021/formulas/mathematics/middle-school/avqir2b7eshtgxaj3mpxf8sf55mqq936h5.png)
so, substituting this values in the formula:
![A=((2x^3-x+8x^2+3x)(4x^2))/(2)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/b7mpw908o2wmo2v081pgbjp0mjdb342t83.png)
Simplifying the expression and joining like terms
![A=((2x^3+8x^2+2x)(4x^2))/(2)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/sc17966y1ukf6siv8ujj8o2vue8c0xvsaa.png)
Multiplying the numerator parentheses:
![A=(8x^5+32x^4+8x^3)/(2)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/5ua43kodtb13st3g1q5hg5xs8uhpopxygk.png)
dividing by 2:
![A=4x^5+16x^4+4x^3](https://img.qammunity.org/2021/formulas/mathematics/middle-school/nnwg16g6827zp7ppo5knwi5z36uz0jqjcn.png)
the simplified expression for the area of this trapezoid is
![4x^5+16x^4+4x^3](https://img.qammunity.org/2021/formulas/mathematics/middle-school/u8vsqd09ppornofe38r9k7zk8n16z6tlaj.png)