Question

the equation x³-x=30
has a solution between 3 and 4
use trial and improvement
method to find its solution correct to1 decimal place
show all the working

Answer 1

when x= 3  27-3= 24 Too small
when x=4   64-4= 60 Too Big


when x=3.3  35.937-3.3= 32.637 Too Big
when x=3.2  32.768-3.2= 29.568  Too Small



when x=3.25 34.328125-3.25= 31.078125 Too Big


The answer to 1 decimal place is 3.2

Be sure to always show the workings to one more decimal place than the answer wants to gain full marks