Question: Solve the inequality 4t2≤9t−2
We rearrange it as follows:
4t2−9t+2≤0
Then, factor this quadratic equation:
(4t−1)(t−2)≤0
The critical values (also called endpoints) are: t1=14,t2=2
So, if we sketched the quadratic 4t2−9t+2, it has x-intercepts (1/4 and 2).
And we want the region below the x-axis (As it is less than 0).
Hence, the region between 1/4 and 2.
Therefore: 14≤t≤2
Here is a sketch: (Using desmos.com)
I hope this helps.