Answer :
Answer is 9.
-3x^2 + 243 = 0
Bring 243 to the right.
-3x^2 = -243
Divide by -3.
x^2 = 243/3 = 81
Tak the square root of both sides.
x = 81^1/2 = 9.
-3x^2 + 243 = 0
Bring 243 to the right.
-3x^2 = -243
Divide by -3.
x^2 = 243/3 = 81
Tak the square root of both sides.
x = 81^1/2 = 9.
[tex]-3x^2+243=0\\
\\
-3x^2=-243\\
\\
x^2=\frac{-243}{-3}\\
\\
x^2=81\\
\\
x=\pm\sqrt{81}\\
\\
\boxed{x=\pm9}[/tex]
