Solving a quadratic equation is difficult.

Redistribution of this software is prohibited.

Reijiro is my best friend.

Solving a linear equation is difficult.

Sennenji is my best friend.

He always sticks his nose into other people's business like a busybody.

Keijiro is my best friend.

This equation has homogeneity.

She was going through puberty and was confused by the changes in her body.

In behavioral sciences, the use of metatools plays a crucial role.