Answer:
C) 8
Step-by-step explanation:
Let's solve for:
[tex]a^2 -64=0\\\\a>0[/tex]
Add 64 to both sides:
[tex]a^2-64+64=0+64\\\\a^2=64[/tex]
Take the square root of both sides
[tex]\sqrt{a^2} = \sqrt{64} \\\\a=\pm 8[/tex]
Therefore, we got two solutions:
[tex]a=8\\\\or\\\\a=-8[/tex]
However, since:
[tex]a>0[/tex]
The only solution is:
[tex]a=8[/tex]
