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Here are the solutions to the math problems:

Вариант 1: Выполните вычитание

a) \( 5 - (-4) = 5 + 4 = 9 \)

b) \( -3 - 6 = -3 - 6 = -9 \)

c) \( 33 - (-7) = 33 + 7 = 40 \)

d) \( -9 - 5 = -9 - 5 = -14 \)

e) \( -8 - (-19) = -8 + 19 = 11 \)

Вариант 2: Выполните вычисления

a) \( 2.49 - 7.8 = -5.31 \)

b) \( -3.5 + 15.6 = 12.1 \)

c) \( -16.6 - 18.1 = -34.7 \)

Вариант 2: Решите уравнение

a) \( x - 36 = 17 \)
\( x = 17 + 36 = 53 \)

b) \( y + 5 = -12 \)
\( y = -12 - 5 = -17 \)

c) \( z - 9 = -9 \)
\( z = -9 + 9 = 0 \)