[tex](a + 4.6) - (a +9 .8) = a + 4.6- a - 9 .8 = - 5.2[/tex]

[tex] - (8.8 - x) - (4.7 + x) = - 8.8 + x - 4.7 - x = - 13.5[/tex]

[tex] - (9.4 + x - y) + (4.1 - y) = - 9.4 - x + y + 4.1 - y = - 5.3 - x[/tex]

[tex](a - b + 6.1) - ( - a - b + 6.1) = a - b + 6.1 + a + b - 6.1 = 2a[/tex]