Idont understand how to do this its factoring quadratics

olume = length * height * width  

Therefore 280 = 4 * (n + 2) * (n + 5)  

Divide both sides of the equation by 4  

70 = (n + 2)(n +5)  

Expand  

70 = n^2 + 5n + 2n + 10  

Subtract 70 from both sides and simplify  

0 = n^2 + 7n -60  

Factor  

(n +12)(n -5) = 0  

Therefore n = -12 or + 5  

As n cannot be less than -2 as you cannot have a negative dimension, it means that n = 5 and the sides are 4, (5 + 2), (5 + 5) = 4, 7 and 10 inches respectively  

Volume is therefore  

4*7*10 = 280 = correct  

Hope this helped!

you estimate that the angle of elevation to the top of the 86th floor (the observatory) is 82 .the total height of the building is another 123 meters above the 86th floor.

leave feedback if u need : )