Letting x be the number of dvds, you could use the equation 8x + 12 = 84 to solve it, which would give you x = 9
r and 5 both make 197
r would be a use of a number that isn't known unless you rearrange the equation
The equation would be 5r = 197 or 5 x r = 197
So you could make r the subject,
And to find it, you could divide 197 by 5
197 / 5 = r
Which then would make r = 39.4
The work is shown above.
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Answer: the third answer (C)
Step-by-step explanation: