2 x + 4*x - 5
x^2 + 4*x - 5 при x = 1/4
x^2 + 4*x - 5
(1/4)^2 + 4*(1/4) - 5
(1/4)^2 + 4/4 - 5
-63/16
-5.0 + x^2 + 4.0*x
-5 + x*(4 + x)
(-1 + x)*(5 + x)