Question

Which of the following is not a solution to the following equation?

x^3-5x^2+4 = 0
x = 0
x = 4.83
x = -0.83
x = 1

Answer 1

0^3 - 5 0^2 + 4 = 4 not 0

1 works
so factor it out
(x-1)(x^2-4x-4) = 0
solve that quadratric
x = [ 4 +/- sqrt(16+16)]/2

= 2 +/- 2.83
= 4.83 and -.83 sure enough

Answer 2

Thanks!