How to solve this equation?

Answer:
x = √(28), or x = 5.292
Step-by-step explanation:
First you distribute the square to the values inside of the parentheses. so it ends up looking like this
5(x^2 - 25) - 9 = 6
add 9 to both sides
so its 5(x^2 - 25) = 15
Then distribute the multiplication of 5 to the contents within the parentheses
so it would be 5x^2 - 125 = 15
add 125 to both sides
you get 5x^2 = 140
divide by 5 on both sides
you get x^2=28
then, take the square root of both sides to reverse the square
√(x^2)=√(28)
and in the end you get x=5.292
but √(28) will probably be fine if your teacher doesn't want u to solve for that kind of stuff.