Answer:
2n
Step-by-step explanation:
Pythagoras 
2 squared plus 2 squared = 8 but you need to find out the root of 8,
square root of 8 is a surd, so answer in that
Not sure what the question is but 3x + 7 is the algebraic expression that would represent this statement.
Because it's decreasing, you use the formula (1-x/100)y with x the percentage decreased which is here 40, and y the number decreased which is here 90
So we get
(1-40/100) * 90
(100/100 - 40/100) * 90
60/100 * 90
5400/100
54
So 90 decreased by 40% is 54
Hope this Helps :)
The answer to your question is F
Well you have to leave x by it self so you would subtract z first and move it to the right now you would be left with m=bx now divide by b to leave the x by itself and get m/b=x
Hope this helps