4 x^2 + 20 x + 25 = 7
Divide both sides by 4:
x^2 + 5 x + 25/4 = 7/4
Write the left-hand side as a square:
(x + 5/2)^2 = 7/4
Take the square root of both sides:
x + 5/2 = sqrt(7)/2 or x + 5/2 = -sqrt(7)/2
Subtract 5/2 from both sides:
x = sqrt(7)/2 - 5/2 or x + 5/2 = -sqrt(7)/2
Subtract 5/2 from both sides:
Answer: x = sqrt(7)/2 - 5/2 or x = -5/2 - sqrt(7)/2
Answer: Option C
Step-by-step explanation:
In group(1), the risk is= 5/2000 x 100
= 0.25
In group(2), the risk is= 5/1000 x 100
= 0.5
The sample relative risk is= 0.25/0.5
= 0.5
So, option C is correct.
