I think the answer is A I’m not sure tho
From the setup of the problem, the "length of the top of the bookcase, measured along the attic ceiling" will be the hypotenuse of a right triangle, the length "AB". We have both the angle between AB and AC and the length of AC (3.24 meters), so we can use trigonometric identities.
The cosine of the 40 degree angle between AB and AC is equivalent to the length of AC divided by the length of AB. Equivalently, we have:

where "h", the hypotenuse, is the length we want. Rearranging the formula to solve for h we have that

which is 4.2295... meters. Converting to centimeters (multiplying by 100) we have that h = 422.95... centimeters, or if we round the value, h = 423 centimeters.
<span>-7 • (a4 - 81a2 - 162)27
-------------------------------- hope it helps
27</span>
<span>First we have to find the sum and the difference of those polynomials- The sum is: ( 3 x^5y - 2 x^3y^4 - 7 xy^3 ) + ( - 8 x^5y + 2 x^3y^4 + xy^3 ) = 3 x^5 - 2 x^3y^4 - 7xy^3 - 8 x^5y + 2 x^3y^4 + xy^3 = - 5 x^5y - 6 xy^3. And the difference: ( 3 x^5y - 2 x^3y^4 - 7 xy^3 ) - ( - 8 x^5y + 2 x^3y^4 + xy^3 ) = 3 x^5y - 2 x^3y^4 - 7 xy^3 + 8 xy^5 - 2 x^3y^4 - xy^3 = 11 xy^5 - 4 x^3y^4 - 8xy^3. The highest exponent in both polynomials is 5. Answer: The degree of the polynomials is 5.</span>
1) neither
2) geometric sequence