Answer :

To find the product of the given four terms, we need to multiply them together step by step.

The given terms are:
[tex]\[ -\frac{1}{2} x^2, \; -\frac{3}{5} xy, \; \frac{2}{3} yz, \; \text{and} \; \frac{5}{7} xyz \][/tex]

First, let's multiply the coefficients (the numerical parts) together, and then we will deal with the variables.

The coefficients are:
[tex]\[ -\frac{1}{2}, -\frac{3}{5}, \frac{2}{3}, \; \text{and} \; \frac{5}{7} \][/tex]

Multiplying these coefficients together:

1. Multiply the first two:
[tex]\[ -\frac{1}{2} \times -\frac{3}{5} = \frac{3}{10} \][/tex]

2. Multiply the result with the third coefficient:
[tex]\[ \frac{3}{10} \times \frac{2}{3} = \frac{2}{10} = \frac{1}{5} \][/tex]

3. Multiply the result with the fourth coefficient:
[tex]\[ \frac{1}{5} \times \frac{5}{7} = \frac{1}{7} \][/tex]

Next, let's consider the variables.

From the given terms:
[tex]\[ -\frac{1}{2} x^2 \times -\frac{3}{5} xy \times \frac{2}{3} yz \times \frac{5}{7} xyz \][/tex]

Combining the variables:
- [tex]\(x^2 \times x \times x \times x = x^5\)[/tex]
- [tex]\(y \times y \times y = y^3\)[/tex]
- [tex]\(z \times z = z^2\)[/tex]

Putting everything together:
[tex]\[ -\frac{1}{2} x^2 \times -\frac{3}{5} xy \times \frac{2}{3} yz \times \frac{5}{7} xyz = \left( \frac{1}{7} \right) x^5 y^3 z^2 \][/tex]

So, the product of the given terms is:
[tex]\[ \boxed{0.14285714285714285 x^5 y^3 z^2 } \][/tex]