Answer:
D (+_ 15)
Explanation:
X^2-225=0
the question is saying to solve the quadratic equation using the roots method.
so first u shift -225 to the other side.
we get: x^2= 225
no we hv x^2
we can shift the power to the other side. When u r shifting powers to the other u will always get a√. Doing so will give us √225.
(U can use a calculator for solving √225)
now solving it will give us +_15.
Here, u hv to be careful. When u r done solving a root over sum, never forget to put the +- sign. or else u can get ur answer wrong.
So, ur final answer is D.(+- 15)
Hope i could explain it to u :D