Algebra equation help

Question

simple equation but I must be getting it wrong somewhere

Because I’m coming up empty

x= -b/2a solve for b

Answer 1

x = -b / 2a

2ax = -b

-2ax = b

Answer 2

x = -b/2a

To solve for b, the question is actually asking for you to find what b equals, and thus isolate "b" to one side of the equal sign. In order to do this, we will move everything away from the right side of the equal sign, and leave b alone.

First, we move the "2a" away. since we are dividing by 2a, we must do the opposite, and multiply by 2a. This cancels out the 2a from the right side of the equation. However, we can't simply multiply by 2a on one side of the equation - whatever we do to one side we must do to the other. So, on the left of the equation, we get x times 2a.

(2a) x= -b/2a (2a)

2ax= -b

Now, we're almost done! However, we haven't isolated "b" to one side of the equation, we've isolated "-b". So, we must "get rid of" the negative sign. Since a negative sign means we are multiplying by negative one, to cancel out the negative sign, we must do the opposite, and divide by -1. (Again, remember - whatever we do to one side we must do to the other, so we must also divide by -1 on the left of the equals sign.)

2ax = -b

can also be written as...

2ax = (-1)b

2ax / (-1) = (-1)b / (-1)

-2ax = b

Now, we have isolated b to one side of the equation, and can successfully say that we have solved for b!