[nathalia305]

how to solve this equation step by step

[J_9]

First multipy 9 by the n and the + 3 and what do you get?

[Unknown008]

All that you need to do is make n the subject of the formula. To do this, you can make use of adding, subtracting, multiplying and dividing, provided what you do on one side, you do the same on the other side.

In your problem, you first need to use the distributive law, that is do what J_9 told you to do.

Then, bring all the terms in 'n' on the same side, by adding, or subtracting those terms.

Bring the terms with no n on the same side.

Add or subtract what is necessary to simplify.

And last, divide or multiply to get 'n' alone.

Post what you come up with :)

[nathalia305]

9n+27=7n-3
correct?

[Unknown008]

Yes, and now, make all the terms in n on the same side. :)

[nathalia305]

9n+7n=27-3 ?

[J_9]

Not quite. Try again. You just can't move them, you have to do some math to move them.

Try dividing from each side and see what you get.

[nathalia305]

Dividing what though?
I'm sorry I don't understand

[KISS]

J9:

Divide? I don't understand that either.

----

9n+27=7n-3
correct?

That is correct so far.

When you move things from one side of the equal sign to the other you can look at it in one of two ways:

1: You have to change the sign. (This isn't a good way to understand what's going on)

-or-

You can add or subtract the same thing from both sides.

so;

9n+27=7n-3

can become 27=7n-9n-3 (changing the sign when 9n moves)

This can also be thought of as

9n+27=7n-3
-9n      -9n
----------------
27     = -3n-3

(sorry, can't get things to line up vertically and it's too late to do it the hard way)

So, see how I have subtracted the same thing from both sides.

It's still not complete. Now add 3 to both sides.

What do you get?

When that's done you have one more step and your done.

[Unknown008]

I'll do this the way I do it :)

From this:



Subtract 7n from both sides;



Do you see what happens? 7n - 7n = 0 on the right hand side.



Now, you could also have subtracted 9n from both sides, from to get , but I'll go on with the one I did above.

So, from , remove 27 from both sides:



27 - 27 = 0, right?



Now, simplify these. What is 9n - 7n? And -3 - 27?