Beth simplified the expression 8 + 10 + 8 + 2 minus (4 times 1.4) minus (4 times 1.4) to find the perimeter of the figure on the grid. On a coordinate plane, a figure has side lengths of 8, 10, 8, 2, (4 times 1.4), (4 times 1.4).

What error did Beth make?
She found the area of the figure instead of the perimeter.
She subtracted the lengths of the diagonal lines instead of adding them.
She used 4 times 1.4 to represent the length of each diagonal line instead of 4.
She added the horizontal and vertical lengths instead of multiplying them.

The position of a moving particle is given by the position function: f(t)=-9t-t^2-0.2t^3+0.1t^4 a. at what time does the particle reverse direction? b. when is the displacement positive? (round one decimal place and answer in interval notation) c. when is the displacement negative? (round one decimal place and answer in interval notation) d. when is the particle’s acceleration positive? (round one decimal place and answer in interval notation) e. when is the particle’s acceleration negative? (round one decimal place and answer in interval notation)