I want the work in English

We use the mirror formula: $\frac{1}{f} = \frac{1}{v} + \frac{1}{u}$

$$\frac{1}{20} = \frac{1}{v_c} + \frac{1}{25}$$ $$\frac{1}{v_c} = \frac{1}{20} - \frac{1}{25} = \frac{5-4}{100} = \frac{1}{100}$$ $$v_c = 100 \text{ cm}$$

Magnification, $M = -\frac{v}{u} = \frac{h_i}{h_o}$

$$M_c = -\frac{100}{25} = -4$$

Image height, h_{ic} = M_c \times h_o = -4 \times 4 \text{ cm} = -16 \text{ cm} $$ The magnitude of the image size is 16 \text{ cm}$. The negative sign indicates an inverted image.

Step 2: Calculate the image distance ($v$) and image height ($h_i$) for the convex mirror.
We use the mirror formula: $\frac{1}{f} = \frac{1}{v} + \frac{1}{u}$

$$\frac{1}{-20} = \frac{1}{v_x} + \frac{1}{25}$$ $$\frac{1}{v_x} = -\frac{1}{20} - \frac{1}{25} = \frac{-5-4}{100} = \frac{-9}{100}$$ $$v_x = -\frac{100}{9} \text{ cm} \approx -11.11 \text{ cm}$$

Magnification, $M = -\frac{v}{u} = \frac{h_i}{h_o}$

$$M_x = -\frac{(-100/9)}{25} = \frac{100}{9 \times 25} = \frac{4}{9}$$

Image height, h_{ix} = M_x \times h_o = \frac{4}{9} \times 4 \text{ cm} = \frac{16}{9} \text{ cm} \approx 1.78 \text{ cm} $$ The magnitude of the image size is approximately 1.78 \text{ cm}$. The positive sign indicates an upright image.

The image height from the concave mirror is $16 \text{ cm}$.
The image height from the convex mirror is $1.78 \text{ cm}$.

Conclusion:
The mirror that forms a bigger image is the concave mirror.

$$\boxed{\text{The concave mirror forms a bigger image.}}$$

For an object placed $25 \text{ cm}$ from a concave mirror with $f = 20 \text{ cm}$ (i.e., the object is between F and C):

• The image is real.
• The image is inverted.
• The image is magnified.
• The image is formed in front of the mirror, beyond the center of curvature (C).

For any real object placed in front of a convex mirror:

• The image is virtual.
• The image is erect (upright).
• The image is diminished (smaller).
• The image is formed behind the mirror, between the pole and the focus.

A driving mirror needs to provide a wide field of view and form erect images so that objects appear in their correct orientation.

• Concave mirrors form inverted images when the object is far from the focus, which is unsuitable for driving. They also have a narrow field of view.
• Convex mirrors always form erect, diminished, and virtual images, and they provide a much wider field of view. This allows the driver to see a larger area behind the vehicle.

Therefore, a convex mirror is more suitable for use as a driving mirror.

$$\boxed{\text{A convex mirror is more suitable for use as a driving mirror.}}$$