Solve by elimenation

0.3x -0.27 =4
0.2x + 0.3y = -37/17

0.3X -0.27Y = 4.Iassumed you mean-.27Y

0.2X +0.3Y = -37/17.
Multiply the 1st. Eq by 2 and the 2nd.
Eq by -3:
0.6X -0.54Y = 8
-0.6X -0.9Y = 111/17 = 6 9/17.
Add the 2 Eq:
-0.63y = 14 9/17 = 14.53.
Y = -23.06

Substitute -23.06 for Y in 1st Eq:
0.3X -0.27(-23.06) = 4.
0.3X +6.226 = 4
0.3X = -2.226
X = -7.42.