√20 = 4.47213
√20 = 4 (nearest integer)
√20 = 4.5 (nearest tenth)
1. This is one confusing question... But here is what I did
x = 2y + 1
y =

+ 2x
So plug in Y to solve for X
x = 2 (

+ 2x) + 1
x =
- 
Not sure if that's completely correct, but I'm positive I didn't make any mistakes...
5. You have to find the multiples of 60 so...
1 60
2 30
3 20
4 15
<span>5 12
<---
7 = 12 - 5</span>
X is -1/2 . Using the Lambert W function.
x^2=16^x => x^2=(2^4)^x
x^2=2^4x => x=2^2x
x=(e^in(2))^2x => x=e^2in(2)x
e^2in(2)x1/x=1
xe^-2in(2)x=1 /*1
-xe^-2in(2)x=-1
-2in(2)xe^-2in(2)x=-2in(2)
W(-2in(2)xe^-2in2x)=W(-2in(2))
-2in(2)x=W(-2in(2))
X=-W(-2in(2))/2in(2)