I'm assuming you mean #10?
So we're given this equation:
In this equation, we a variable of <em>b</em>. We want to solve for <em>b</em> by isolating it, or setting it alone. We see that on the side with <em>b</em> on it, it is being subtracted by 5. We want to the opposite in order to isolate <em>b</em>.
Remember that when you do one thing to one side of the equation, you
must do it to the other side as well. We can add 5 on both sides to cancel out the negative 5 on the left.
Therefore we know that <em>b</em> does
not equal -10, which can be represented as:
So you have to (a) color the hair yellow.