The expression is ambiguous, but I'll assume you mean:

$$\frac{3/4(-8)}{2-3}$$

The order of operations are:

1. Solve what's in the paranthesis

2. Multiply (*) and divide (:)

3. Add (+) ans subtract (-)

We get:

$$\frac{3/4(-8)}{2-3} = \frac{3/-32}{-1}$$

Multiply both the numerator (top) and denominator (bottom) with -1

$$\frac{3/32}{1}=3/32 = 0.09375$$

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