Answer:
<em>Correct choice: 72</em>
Step-by-step explanation:
<u>Multiplication</u>
In math, to multiply means to add equal groups. For example, 5 groups of 7 people add up to 5*7=35 people.
When multiplying variables (letters), it's common to omit the cross (x) or dot (.) signs to indicate multiplication.
The expression cd, when c and d are separate variables, should be interpreted as c by d.
We are given c=9 and d=8, thus
cd = 9*8 = 72
Correct choice: 72