Question

One root of the quadratic equation x^2 − 2x + m = 0 is 9. If the other root is n, what is n−m?

Answer 1

`9^2-2*9+m=0\\ \\ 81-18+m=0\\ \\ m=-63`


`x^(2) -2x-63=0\\ \\ \Delta=(-2)^2-4.1.(-63)=4+252=256\\ \\ x=(2 \pm 16)/(2)\\ \\ x_1=(18)/(2)=9\\ \\ n=x_2=(-14)/(2)=-7\\ \\ n-n=-7-(-63)=-7+63=56`