TeX Quellcode:

{\left(3x+5y\right)^2+4\left(3x-5y\right)^2 = 9x^2+30xy+25y^2+4\left(9x^2-30xy+25y^2\right) = 9x^2+30xy+25y^2+36x^2-120xy+100y^2 = 45x^2-90xy+125y^2}