Question 166092
2(a+b)=94 
{{{2a+2b=94}}}     distribute
4(a-9)=3b-23
{{{4a-36=3b-23}}}  distribute
{{{4a-3b=13}}}

now we have 2a+2b=94
:::         4a-3b=13
when you use elimination method in linear equations you multiply one or both equations by a constant that will help eliminate one variable. I n our case we can either multiply the top equation by 4 and the bottom by -2 to eliminate the a variable  or we can multiply the top by 3 and the bottom equation by 2 and get rid of the b variable. I choose the 2nd option

:          3(2a+2b=94)--->6a+6b=282
:          2(4a-3b=13)--->8a-6b= 26

now notice when we add 
these two together that
the b terms are eliminated
and we end up with ------- 14a=308--->{{{a=22}}}

now we can plug a's value back into either of the original equations solving for b

----------> 2(22)+2b=94----->44+2b=94--->2b=50---{{{b=25}}}

hope that helps explain solving linear equations by elimination