Question

Como resolver: (x+40).x=1200

Answer 1

$(x+40)x=1200\\ \\ x^{2} +40x-1200=0\\ \\ \Delta=40^2-4.1.(-1200)=1600+4800=6400\\ \\ x=\frac{-40 \pm 80}{2}\\ \\ x_1=-60\\ \\ x_2=20$