Question

Factor completely 9x^2-25

Answer 1

Answer:

$9x^{2} - 25$ = (3x -5)(3x+5)

Step-by-step explanation:

Here, the given expression  is $9x^{2} - 25$

Now, we know that $9 = 3^{2} , 25 = 5^{2}$

So, the given expression is transformed in to

$9x^{2} - 25$  = $(3x)^{2} - 5^{2}$

Also, by ALGEBRAIC IDENTITY

$a^{2} - b^{2} = (a-b)(a+b)$

Similarly here taking :  a = 3x and b =5

$(3x)^{2} - 5^{2}$ = (3x -5)(3x+5)