A system of equations consists of y x3 5x 1 and y x The

A system of equations consists of y = x3 + 5x + 1 and y = x.

The equations are equal at approximately x =

a.    -.25

b.    -.5

c.    .5

d.    .25

Solution

Given y = x³ + 5x + 1 and y = x

they are equais when y = y

x³ + 5x + 1 = x

x³+4x+1 = 0

The roots of the polynomial x³ + 4x + 1 are:

x1 = 0.24627

x2 = 0.12313 + 2.01134 i

x3 = 0.12313 2.01134 i

the two equations are equal at -0.25

ans: a