TeX Quellcode:
{\left(-4a+7b\right)\left(-7a+4b\right) = -4a\cdot\left(-7a\right)-4a\cdot 4b+7b\cdot\left(-7a\right)+7b\cdot 4b = 28a^2-16ab-49ab+28b^2 = 28a^2-65ab+28b^2}