What is the sum of 2x+1 and its opposite?

Zero. The sum of anything and it's opposite is zero, that's how an opposite is defined . In this case, the opposite of 2x+1 is -(2x+1)=-2x-1 by the distributive property . Adding like terms, 2x+-2x+1+-1=0+0=0.

the direct variation says that:

then the equation is of the form is given by:

            where k is the constant variation.

from the given table:

consider any value of x and m(x)=y

x = 2 and m(x)=y = 3

substitute these value in [1]; we have;

divide both sides by 2 we get;

⇒

check:

put x = -1 and m(x) = -1.5

substitute in the equation:

-1.5 = -1.5                   true

therefore, the function m(x) represents a direct variation

graph of this function as shown below: