[tex]2x^2+17x+21=0\\D=17^2-4*2*21=121=11^2\\x_1=\frac{-17+11}{4} =-1,5\\x_2=\frac{-17-11}{4} =-7[/tex]
zeros of 2x^2+17x=-21 are (-7;0) and (-1,5)
P.S. Hello from Russia
