Answer:
[tex]0.8\, t^{12}[/tex] (assuming that [tex]a \ge 0[/tex].)
Step-by-step explanation:
The rule [tex]a^{2} - b^{2} = (a + b)\, (a - b)[/tex] describes a way for factoring the difference between two perfect squares [tex]a^{2}[/tex] and [tex]b^{2}[/tex].
Setting [tex]a^{2} = 0.64\, t^{24}[/tex] and [tex]b^{2} = 9[/tex] would ensure that [tex](a^{2} - b^{2})[/tex] match the given expression.
Take the square root of both sides of the equality [tex]a^{2} = 0.64\, t^{24}[/tex]. Make use of the fact that for all [tex]x \ge 0[/tex], [tex]\sqrt{x} = x^{1/2}[/tex].
[tex]\displaystyle \sqrt{a^{2}} = \sqrt{0.64\, t^{24}}[/tex].
[tex]\begin{aligned} a &= \left(\sqrt{0.64}\right)\, \sqrt{t^{24}} \\ &= 0.8\, (t^{24})^{1/2}\\ &= 0.8 \, t^{24 \times (1/2)} \\ &= 0.8\, t^{12}\end{aligned}[/tex].