Question

2x(a+3b)+3c=131 iar c+2b=19 ? pls

Answer 1

c+2b=19 <=> 3c+6b=57
2x(a+3b)+3c=131 <=> 2a+6b+3c=131 <=> 2a+57=131 <=> 2a=74 <=> a=37

Answer 2

$c+2b=19 \\ 2*(a+3b)+3c=131 \\ 2a+6b+3c=131 \\ 2a+3*(2b+c)=131 \\ 2a+3*19=131 \\ 2a+57=131 \\ 2a=131-57 \\ 2a=74 \\ a=\frac{74}{2} \\ a=37$