How do you solve the system $9a+2b=10$ and $9a-2b=10$ ?

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Answer 1 · 2015-06-17T01:23:54

$a=10/9$
$b=0$

I would add the two equation together as:
${9a+2b=10$
${9a-2b=10$
$----=-$
$18a+//=20$

So that $a=20/18=10/9$ and using this value into the first equation:
$9*10/9+2b=10$
$b=0$

How do you solve the system 9a+2b=109a+2b=10 and 9a-2b=109a-2b=10?