To evaluate this expression, we need to follow the order of operations. The first step is to perform any calculations inside parentheses. In this case, we have (6+2)^2. 6+2 is 8, so (6+2)^2 is 82, which is 64.
Next, we need to perform any exponentiation. We have 7*64 - 3.2.
Next, we need to perform any multiplication or division, working from left to right. We have 7*64 - 3.2, which simplifies to 448 - 3.2.
Finally, we need to perform any addition or subtraction, working from left to right. We have 448 - 3.2, which simplifies to 444.8.
Therefore, the final result of the expression is 444.8.