# Please help me solve the following pair of simultaneous equations algebraically.

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• October 23rd 2010, 06:36 AM
mathsstudent
Please help me solve the following pair of simultaneous equations algebraically.
Any non-integer solutions should be given as fractions in their simplest form.

5a-b=9
a+6b=-3

Also, please show working.
• October 23rd 2010, 06:39 AM
Prove It
Start by multiplying the first equation by 6. Then add the two equations together to eliminate $b$.
• October 23rd 2010, 06:49 AM
mathsstudent
hi,
what's next?
• October 23rd 2010, 06:52 AM
Prove It
Why not show what you have done and where you are stuck?
• October 23rd 2010, 07:01 AM
mathsstudent
I multiplied the first equation by 6
and added the 2 equations together

30a - b = 54
a+6b = -3

31 + b =51
• October 23rd 2010, 07:02 AM
Prove It
It should actually have been

$30a - 6b = 54$

$a + 6b = -3$.

Now try adding the equations together. What do you get?
• October 23rd 2010, 07:06 AM
mathsstudent
Is it

31a+12b=51?

Thanks
• October 23rd 2010, 07:10 AM
Unknown008
No, adding them gives:

(30a - 6b) + (a + 6b) = 54 -3

31a = 51

b - b = 0