The answer to your Question is
is false
Because they are not man made and are part of the earth's natural features caused by the the weathering and erosion of the earth.
To change the equation, you'd have to take the square root of both sides. When you do this, x^2 cancels out leaving you with x = sqrt(y)
If you need help on the other ones, all you have to do is solve for x by using either addition/subtraction or dividing/multiplying.
A thermometer, a barometer, a sling psychrometer, and a rain guage
