We have that
t²<span> – 81
</span>
we know that
A difference of two perfect squares, <span> (A</span>²<span> - B</span>²)<span> </span><span>can be factored into </span><span> (A+B) • (A-B)
</span> let
A²-------> t²
B²-------> 9²
then
(t² – 9²)------->(t+9)*(t-9)
the answer is
(t+9)*(t-9)
Let's use ratio and proportion or rates to solve this
If there is 5/6 cup of cinnamon in a 3/4 pound of spice mix, how many are in a pound?
5/6=3/4
?=1
1/ (3/4)*5/6=10/9
Therefore there are 10/9 cups of cinnamon in 1 pound of spice mix
