Answer:
4.6
Step-by-step explanation:
X^3-6x=72
Solution between 4 and 5 correct to one decimal place
This means There are 10 Possible solution (4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0)
Let x=4.1
X^3-6x=72
=4.1^3-6(4.1)
=68.921-24.6
=44.321
This means 4.1 is far from the answer
Let's try a bigger number
Let x=4.8
X^3-6x=72
4.8^3-6(4.8)
=110.592-28.8
=81.792
Let x=4.7
X^3-6x=72
4.7^3-6(4.7)
=103.823-28.2
=75.623
Let x=4.6
X^3-6x=72
4.6^3-6(4.6)
=97.336-27.6
=69.736
It can be said that the solution is between 4.6 and 4.7
Let x=4.62
X^3-6x=72
4.62^3-6(4.62)
=98.611128-27.72
=70.891128
Let x=4.64
X^3-6x=72
4.64^3-6(4.64)
=99.897344-27.84
=72.057344
Let's=4.65
X^3-6x=72
=4.65^3-6(4.65)
=100.544625-27.9
=72.644625
This is greater than 72
We can conclude that the closest answer is 4.64
Let x=4.64
X^3-6x=72
4.64^3-6(4.64)
=99.897344-27.84
=72.057344
Approximately 72
4.64 to one decimal place=4.6
