160 test=100%
Therefore:
160 test------------------100%
104 test------------------ x
x=(104 test*100%) / 160 test=65%
Answer: 104 test is the 65% of 160 test
When it says x and y are directly related it means that x is multiplied by something to get y. To solve you divide y by x which is 840 divided by 6. Which is 140 then you multiply and solve so the y value for 5 is 700. The x value for 420 is 3 and the y value for 4 is 560.
It is obvious that the radicals with negative sign tends to be less than those that are positive. So from there you already know a basic order. Now to be sure, you can use a calculator or just solve by squaring the whole number to find the radical form.
Solve for y
let's put our equation first
Flip the equation
Now follow the rule of 
_________________________
_________________________
add 
to both sides
Divide both sides by 
would equal 
