8х-9у-21=0,3х-2у-12=0

Question

8х-9у-21=0,3х-2у-12=0

Answer 1

11х-11у-33=0
{
11х-11у=33

х-у=3

х=3+у

8*(3+у)-9у-21=0
{
24+8у-9у-21=0

 -у+3=0

  у=3

 Х=3+3=6