How do you factor x2 - x - 35?

Answer 1

Factors of 35 are 1 & 35 or 5 & 7. Can't get a -1 out of those so you have to use the quadratic formula: minus b +/- sqrt (b^2 - 4 x a x c) all over 2 x a. this gives (1 +/- sqrt (1+140) )/2 = (1 +/- 11.874)2 = 6.437 or -5.437 Check: 6.437^2 -6.437 = 41.435 - 6.437 = 34 .998. Near enough. If the original equation had been x^2 - 2x - 35 it would have factored nicely as (x + 5)(x -7)