Answer :

To solve the expression [tex]\(-r^2 \left( r^2 - 3r \right)\)[/tex] and simplify it, we can follow these steps:

1. Distribute the [tex]\(-r^2\)[/tex] term:
We need to multiply [tex]\(-r^2\)[/tex] with each term inside the parenthesis [tex]\( (r^2 - 3r) \)[/tex].

[tex]\[ -r^2 \left( r^2 \right) + (-r^2) \left( -3r \right) \][/tex]

2. Multiply [tex]\(-r^2\)[/tex] by [tex]\( r^2 \)[/tex]:
This gives us:

[tex]\[ -r^2 \cdot r^2 = -r^{4} \][/tex]

3. Multiply [tex]\(-r^2\)[/tex] by [tex]\(-3r\)[/tex]:
This gives us:

[tex]\[ -r^2 \cdot -3r = 3r^{3} \][/tex]

4. Combine the results:
Now, combine the results from the distribution steps:

[tex]\[ -r^4 + 3r^3 \][/tex]

5. Factor the combined expression:
We can factor out a common factor of [tex]\( r^3 \)[/tex]:

[tex]\[ -r^4 + 3r^3 = r^3 (3 - r) \][/tex]

Therefore, the simplified expression is:

[tex]\[ r^3 (3 - r) \][/tex]

This is the product and the simplified form of the given expression [tex]\(-r^2 \left( r^2 - 3r \right)\)[/tex].