This is just cylinder surface area, right? Equation for that would be 2πrh+2πr^2. If we input the data given from the image, it’d be (2 x π x 3.5 x 4)+(2 x π x 3.5 x 3.5). (4 is the height, and I found the radius by dividing the diameter, 7, in half, which is 3.5.) if u plug that into a calculator, u get 164.93.
(a^3 - 2a + 5) - (4a^3 - 5a^2 + a - 2)
=a^3 - 2a + 5 - 4a^3 + 5a^2 - a + 2
= -3a^3 + 5a^2 - 3a + 7
Let's use the SAS postulate! SAS means Side, Angle, Side. I would sometimes write this the other way and get in trouble, haha.
It technically means if a triangle that has a congruent angle between two congruent sides, it means it is congruent. Here is a picture.
3√27
= 9√3
I hope that's help and sorry for the late answer ^..^