Care to elaborate, what I can say right now is just that a virus is a malicious program that invades your computer and multiplies itself across several programs and folders. a viral video is only similar because it becomes really popular across the internet and "spreads" throughout the internet by fame. hope that help... oh and id say this is more of a computers question.
The mathematical expression does not seem clear but I have made an attempt to make sense of what is implied.
Answer:
<em>a</em> = 4, <em>b</em> = 2, <em>c</em> = 16, <em>d</em> = 9
Step-by-step explanation:

Solving the first part of the question by indices,

Comparing the rightmost term with the second term in the question,
<em>a</em> = 4, <em>b</em> = 2
Solving on,

Comparing with the final term in the question,
<em>c</em> = 16 and <em>d</em> = 9
Therefore,
<em>a</em> = 4, <em>b</em> = 2, <em>c</em> = 16, <em>d</em> = 9
The information shown here only shows a principal sum, a rate of interest and a period or time. There is no question as to what is needed. But suppose the need is for simple interest, then we calculate using the given information and the formula:
I = PRT
where I is simple interest, P is the principal, R is the rate per year, and T is time
P = 290, T is 6 months which is 0.5 years, R = 12.5 % which is written as 0.125 in decimal fraction.
I = 290 × 0.125 x 0.5 → I = 18.125
Therefore after 6 months , the interest earned will be 18. 125 dollars