2x-3y=12

x=4y+1
substitution, elemenation

in this case, substitution is your obvious choice

sub the 2nd into the 1st.

2(4y+1) - 3y = 12
8y + 2 - 3y = 12
5y = 10
y = 2

sub into the 2nd
x = 4(2) + 1 = 9

x = 9 , y = 2