Question

18=-5b-17 (solve for b) grad lvl. 7

Answer 1

The answer is B= -7 because when you add the 17 to get rid of it and balance out the sides, you add it to 18 and get 35. Then you have -5b left and you have to decide the -5 in order to get the variable by itself.

Answer 2

Answer:

b = -7

Step-by-step explanation:

If you want, you can flip the equation around so that it's easier to look at. I usually do this when working with an equation because it seems more natural to me, but this is completely up to you.

-5b-17=18

We need to get "b" by itself since we don't know what it is. Everything else is "known" - we can say that 18 is 18, -5 is -5, but we don't know what "b" is. Let's start by adding 17 to both sides. By doing this, we get rid of the -17 on the left, bringing us one step closer to the answer!

-5b-17 (+17) = 18 (+17)

---remember you have to add to both sides or you mess up the meaning of "="

-5b = 35

Now, all that is left is that -5 attached to the "b". We can get rid of it by dividing both sides by -5. This will remove it from the left side!

(-5b)/-5 = (35)/-5

b = -7 (remember that a positive divided by a negative makes it negative!)

Some advanced notes (look here if you want help with the specific topics used above):

1. If I have an statement that says 0=0 and I add 2 to one side, I have to add it to the other side to still make it equal.

0 = 0 + 2;        0=2           (bad math, 0 isn't the same as 2!)

2+0 = 0+2;      2=2           (good math!)

2. Doing something like dividing on a multiplier is what is called an "inverse operation" and results in a multiplying of 1. It's easier to see:

-5b = 35

(-5b)/-5 = (35)/-5

--- dividing a number by itself gives a 1, like saying 2/2 or 10/10, so the -5's cancel on the left, leaving a 1

(-5b)/-5 = (35)/-5

1*b = (35)/-5

Hope this helps!