[tex] - 3(5x - 3y) - 4( - 2x + 6y) = \\ -1 5x + 9y + 8x - 24y = \\ - 7x - 15y = - 7 \times ( - 2) - 15 \times 0.1 = \\ 14 - 1.5 = 12.5[/tex]

[tex] - 9(3x - 7y) - 8(11x - 2y) = \\ - 27x + 63y - 88x + 16y = \\ - 115x + 79y = \\ - 115 \times 0.02 + 79 \times ( - \frac{12}{13} ) = \\ - 2.3 - \frac{948}{13} = - 2 \frac{3}{10} - 72 \frac{12}{13} = \\ - 2 \frac{39}{130} - 72 \frac{120}{130} = - 74 \frac{159}{130} = \\ - 75 \frac{29}{130} [/tex]