- ax - bx + ab - ${x}^{2}$ = $\left({{{x}{+}{b}}}\right)\left({{{a}{-}{x}}}\right)$
- ${x}^{2}$ - ${y}^{2}$ + 4x + 4 = $\left({{{x}{+}{y}}}\right)\left({{{x}{-}{y}{+}{4}}}\right)$
- ax + ay - 3x - 3y = $\left({{{a}{-}{3}}}\right)\left({{{x}{+}{y}}}\right)$
- xy + 1 - x - y = $\left({{{x}{-}{1}}}\right)\left({{{y}{-}{1}}}\right)$