2.1x + 4.2y = 14.7 is the same as x + 2y = 7 (divide both sides by 2.1)
-5.7x-1.9y=-11.4 is the same as 3x + y = 6 (divide both sides by -1.9)
Rearrange the first equation to get x = 7 - 2y and substitute into the second equation, 3(7 - 2y) + y = 6, 21 - 6y + y = 6, 5y = 15, y = 3
Substitute y = 3 into the first equation x + 2(3) = 7, x = 1
x = 1 and y = 3