4x^2+40x+85 There are no like terms.
Looks good to me. Calculation is correct. Although you might want to add to #1 your description; that the width of the rectangle is the circumference of the circle (w = 2πr) and that you add the surfaces together to get the total surface area.
total surface area = area of rectangular part + area of circular parts
SA = 2πrL + 2πr²
Complementary angles --- they add up to 90 degrees
Total= Car Cost + (Car Cost * Tax %)
Total= $16,800 + ($16,800 * 6.25%)
convert % to decimal form; divide % by 100
Total= $16,800 + ($16,800 * 0.0625)
multiply inside parentheses
Total= $16,800 + $1,050
Total= $17,850
ANSWER: The total cost for the used car with tax is $17,850.
Hopd this helps! :)