-2b + -b =

-2b + -b = -3b

well the answer depends on what number B is.

To solve the equation -2b + -b = 0, let's simplify the left side of the equation by combining like terms.

Combining the variables, we have -2b + -b = -3b.

So the equation becomes -3b = 0.

To solve for 'b,' we need to isolate the variable by dividing both sides of the equation by -3:

-3b / -3 = 0 / -3

This simplifies to:

b = 0

Therefore, the solution to the equation -2b + -b = 0 is: b = 0.