(7x++1) how would you subtract this

(7x+3)-(2x+1) = 7x+3-2x-1 = 7x-2x + 3-1 = 5x +2

Surface Area of a cylinder 2(π•r²)+(2π•r)•h

So

If the diameter is 8 then the radius is 4. the height is 5.

so you have, 2(3.14•4²)+(2•3.14•4)•5

solve. PEMDAS
Parentheses & Exponents first.
2(3.14•16)+(2•3.14•4)•5
2(50.24)+(6.28•4)•5
2(50.24)+(25.12)•5
Multiplication & Division second (left to right)
100.48+125.6
Add & Subtract (left to right)
226.08cm