Now, immediately by looking at the function, you already know that it is a quadratic function because it is of the degree 2.
This allows you to take 2 routes:
1.) By factoring (if possible)
2.) Quadratic Formula
Keep in mind, if route 1 is possible, it will take a lot less time to complete. Luckily, your function is factorable.
Through factoring, you get (2x+3)(2x-3) = 0
So now, you have to make the left side equal 0.
You can accomplish by making (2x+3) = 0
or by making (2x-3) = 0
As a result of simple algebra, you get x = 3/2 and x = -3/2.
You should get the same answer if you use the quadratic formula.
(2x-3)(2x+3)=0,
the rule here is a^2-b^2=(a-b)(a+b)
So, 2x-3=0 or 2x+3=0
therefore, 2x=3 or 2x=-3
hence, x=3/2 or x=-3/2
so the final answer is x=1.5 or x=-1.5 . pick whichever u like or need it both answers to the value of x is right. Now i explained to my best so might better choose me as the best answer.
4x^2-9=(2x-3)(2x+3). (expand the right side and you will see that i am right) (you should memorize this way of factorizing polynomials) (this is called difference of squares)
anyway, since (2x-3)(2x+3)=0,
either 2x-3=0 OR 2x+3=0.