3X-15: x²-25 X x + 4 • 3X+12

The expression given in the image is:

$$ \frac{x+4}{3x-15} \cdot \frac{3x+12}{x^2-25} $$

Let's simplify this expression by factoring the numerators and denominators:

$$ \frac{x+4}{3(x-5)} \cdot \frac{3(x+4)}{(x-5)(x+5)} $$

Now, we can cancel out common factors. The factor of 3 can be cancelled:

$$ \frac{x+4}{(x-5)} \cdot \frac{(x+4)}{(x-5)(x+5)} $$

Multiplying the fractions gives us:

$$ \frac{(x+4)(x+4)}{(x-5)(x-5)(x+5)} = \frac{(x+4)^2}{(x-5)^2(x+5)} $$

The simplified expression is:

$$ \frac{(x+4)^2}{(x-5)^2(x+5)} $$

Answer: $$\frac{(x+4)^2}{(x-5)^2(x+5)}$$