9 × x = 9x
-5 × x = -5x
9 × 4 = 36
-5 × 4 = -20
3 × 2 = 6
3 × -x = -3x
9x - 5x + 36 - 20 = 6 - 3x
4x + 16 = 6 - 3x
4x - 3x = - 16 + 6
x = - 10
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