Answer:
x = - 3 ±
Step-by-step explanation:
x² + 6x + 7 = 0 ( subtract 7 from both sides )
x² + 6x = - 7
using the method of completing the square
add ( half the coefficient of the x- term )² to both sides
x² + 2(3)x + 9 = - 7 + 9
(x + 3)² = 2 ( take square root of both sides )
x + 3 = ± ( subtract 3 from both sides )
x = - 3 ±
Answer:
2010.
Step-by-step explanation:
We have been given an exponential growth formula , which represents number of passengers traveling by airplane since 1990.
To find the year in which 900 million passengers will travel by airline, we will equate the given formula by 900 and solve for t as:
Take natural log of both sides:
Using property , we will get:
This means that in the 20th year since 1990, 900 million passengers would travel by airline.
Therefore, 900 million passengers would travel by airline in 2010.