Which of the following equations has a root in common with x^2−7x+10=0 ?	Select:
A) x^2+5=0
B) x^2-x-1=0
C) x^2-6x+5=0
D) x^2-2x-1=0
E) x^2-1=0
If we carefully look at the given equation we can arrange it in the following manner:   (x-5)(x-2) = 0   so the two roots are 5 and 2.   Now put 5 and 2 in given equations. The equation in which one of them gives value 0, that will be our answer.   (A) putting 5: we get 30; Putting 2 we get 9. Reject this option [by the way x^2+1 cannot have real roots]   (B) putting 5: we get 19; Putting 2 we get 1. Reject this option too [by the way x^2-x-1 cannot have real roots]   (C) putting 5: we get 0. This is the equation.   We are lucky. No need to check other options.   x^2-6x+5=0 is the answer.
<result>C</result>
Which of the following equations has a root in common with x^2−7x+10=0 ?