Hi there!
We can find the zeros of a function by solving f(x) = 0. We find the following:
[tex]3 {x}^{2} - 300 = 0[/tex]
Add 300 to both sides.
[tex]3 {x}^{2} = 300[/tex]
Divide by 3.
[tex] {x}^{2} = 100[/tex]
Take the root and minus root of both sides.
[tex]x = \sqrt{100} = 10 \\ or \\ x = - \sqrt{100} = - 10[/tex]
Therefore, the zeros are
x = 10 and x = -10.
~ Hope this helps you!