Posted by julez on Saturday, October 29, 2011 at 7:07pm.
let z = x^2 then z^2 + 3 z - 4 = 0 (z-4)(z+1) = 0 z = 4 or z = 1 so x^2 = 4 or x^2 = 1 so +/- 2 and +/- 1