Solve the inequation:5−2x3 ≤ x6−5, where x ∈ N.
{8, 9, 10 ……..}
(5−2x)3≤x6−5
Multiplying both sides by 6, we get:
6[(5−2x)3]≤6[x6−5]
or 2(5−2x)≤x−30
or 10−4x−10≤x−30−10
or −4x≤x−40
or −4x−x≤x−40−x
or −5x≤−40
Dividing both sides by -5, as the number is negative, so the sign of inequality is reversed.
or −5x−5≥−40−5
or x≥8
Hence, the solution set is {8, 9, 10 ……..}.