from the first equality we have
3x - 6y = 2
3x = 2 + 6y
x = 2/3 + 2y
we replace x by this value in the second equality
4 * (2/3 + 2y) + 3y = -1
8/3 + 2y + 3y = - 1
5y = - 3/3 - 8/3
5y = - 11/3
y = -11/15
and we can get x now :
and x = 2/3 + 2*(-11/15)
x = 2/3 - 22/15
x = 10/15 - 22/15
x = - 12/15
check
3 * (-12/15) - 6 * (-11/15) = -36/15 + 66/15 = 2
