factoring completely

[itsallforyou]

factor: 3x2 - 75

3(z-5)(z-5)

that's what i have so far.. i was just wondering if i needed to factor it more, or what...

 

[tkhunny]

How did it change from 'x' to 'z'?

Other than that, what else did you have in mind?

 

[Denis]

Not quite:
3x^2 - 75 = 3(x^2 - 25) = 3(x - 5)(x + 5)