Answer:
, 
, 
Step-by-step explanation:
In this problem we have that
we have
substitute the values and solve for x
Group terms that contain the same variable in the right sides
Combine like terms in the right side
<u><em>Find the value of bd</em></u>
Find the value of bc
<u><em>Find the value of cd</em></u>
The first letter can be any one of 8. For each of those . . .
The second letter can be any one of the remaining 7. For each of those . . .
The third letter can be any one of the remaining 6. For each of those . . .
The fourth letter can be any one of the remaining 5. For each of those . . .
The fifth letter can be any one of the remaining 4.
The total number of possibilities is (8 x 7 x 6 x 5 x 4) = <em>6,720</em> .
(That's 8! / 3! .)
Note:
If you're allowed to use the same letter more than once,
then there are 8 choices for each of the 5 letters.
The total number of possibilities then is (8 x 8 x 8 x 8 x 8) = 32,768 .
(That's 8⁵ or 2¹⁵ .)
(3 - 2)(3 + 21) = 9 + 63 - 6 - 42 = 72 - 6 - 42 = 66 - 42 = 24 (I got 24 as my final answer)
