Answer:
75
Step-by-step explanation:
Square both sides. 225=3x^2
divide both sides by 3
x^2=75
x=√75= 5√3
[tex]15 = x \sqrt{3} \\ \\ 1. \: 15 = \sqrt{3x} \\ 2. \: \frac{15}{ \sqrt{3} } = x \\ 3. \: x = \frac{15}{ \sqrt{3} } [/tex]
