f(x)=x7−2x4−4x3+8 ⇒x4(x3−2)−4(x3−2) f(x)=(x3−2)(x4−4) For finding solution, let f(x)=0 (x3−2)(x4−4)=0 ⇒x3−2=0 ...(i) or x4−4=0 x=2
1
3
or x4=4 x2=±2 When x2=2 and when x2=−2 x=±2
1
2
and x=2
1
2
i From Eq. (i), we get x3−2=0 x3−(3√2)3=0 ⇒(x−2
1
3
)(x2+2
2
3
+2
1
3
x)=0 ⇒x−2
1
3
=0 or x2+2
1
3
x+2
2
3
=0 ⇒x=2
t
3
x=
−2
2
3
±√22∕3−4.22∕3
2
x=
−21∕3±21∕3√3i
2
x=
21∕3(−1+√3i)
2
=21∕3ω ∴ Solution set ={21∕3,21∕3ω,21∕2i,−21∕2}.