# Thread: Solving linear equations.

1. ## Solving linear equations.

How can I solve this?

((5p-4)/6) - ((2p+3)/2) = 7

In my text book it says the answer is p = -55 but I've tried and can't get this.

Thanks.

2. Hello,

Put the fractions in the left hand side of the equality on the same denominator (6).

Then, do the same for 7. 7=42/6 and multiply both sides by 6.

After that, you may solve it like a normal equation... Can you show a bit of your work ? To see if you're going the right way

3. Originally Posted by Moo
Hello,

Put the fractions in the left hand side of the equality on the same denominator (6).

Then, do the same for 7. 7=42/6 and multiply both sides by 6.

After that, you may solve it like a normal equation... Can you show a bit of your work ? To see if you're going the right way
I keep ending up with p = -37

I did...

((5p-4)/6) - ((6p+9)/6) = 42/6

5p-4-6p+9=42 (multiplied by 6)

-p+5=42

-p=37

4. Originally Posted by Mymble
I keep ending up with p = -37

I did...

((5p-4)/6) - ((6p+9)/6) = 42/6

5p-4- (6p+9) =42 (multiplied by 6) Mr F says: USE BRACKETS!

5p - 4 - 6p - 9 = 42 etc.

-p+5=42

-p=37

Ahhhhh the benefits of showing working. What you should have done is in red. The really important thing is in blue!

5. Originally Posted by Mymble
I keep ending up with p = -37

I did...

((5p-4)/6) - ((6p+9)/6) = 42/6

5p-4-6p+9=42 (multiplied by 6)

-p+5=42

-p=37

Originally Posted by mr fantastic
Ahhhhh the benefits of showing working. What you should have done is in red. The really important thing is in blue!
Oh!
I think I understand that...
Because it's minus (6p+9) the +9 becomes -9?

So...
((5p-4)/6) - ((6p+9)/6) = 42/6

5p-4-6p-9=42

-p+=55

-p=55

p=-55

Thanks so much!

6. That's it ^^

The - sign is distributed into the parenthesis

When you substract : -(a+b) this means you substract a AND b, so it's like -a-b

7. Originally Posted by Mymble
Oh!
I think I understand that...
Because it's minus (6p+9) the +9 becomes -9?

So...
((5p-4)/6) - ((6p+9)/6) = 42/6

5p-4-6p-9=42

-p+=55

-p=55

p=-55

Thanks so much!

ps: And thankyou for your lovely manners!

8. Thankyou very much for your help both of you.

Sorry if it seemed a silly mistake.

9. Originally Posted by Mymble
Thankyou very much for your help both of you.

Sorry if it seemed a silly mistake.
As long as you learn from it, it's certainly not silly.