What are the solutions to the equation x2 = 81? A. 40.5 only B. 40.5 and –40.5 C. 9 and –9 D. 9 only
\(x^2=81\ then\ x=9\ and\ x=-9\\\\because:(-9)^2=81\ and\ 9^2=81\)
\(x^2=81\to x=-\sqrt{81}\ and\ x=\sqrt{81}\to x=-9\ and\ x=9\)