Subject: Integers

My daughter has an assignment in math that includes this equation:

-6b+5= -10

I've tried to help her with a scale. We've figured that you subtract 5 from each equation so its not -6b = -15. Is this correct and can you help us figure out the next step? Her name is Shelley and she is in 8th grade (independent study program).

Thank you.

I think that a scale is a useful analogy for this problem. I would however try to eliminate the negatives just to make it easier to understand at this stage. Start with

-6b + 5= -10

Add 10 to both sides to get

-6b + 15 = 0

Now add 6b to both sides and the equation becomes

15 = 6b

Notice that both 15 and 6 are divisible by 3 so divide both sides by 3 and you have

2b = 5

Finally divide both sides by 2 to get

b = 5/2 = 2 1/2

For this last step it may help to think of something familiar. If two b's cost $5 then one b costs $2.50



Go to Math Central