Question 679397
Let L = the number in millions of landlines.
Let x be the number of years, starting at x = 0 in 2010
Then the landline equation is
(A) L = -4x + 200, as it is decreasing 4 million a year, starting w/200 million in 2010.
Let W = the number in millions of wireless phones.
Then the wireless equation is
(B) W = 20x + 86, as it is increasing by 20 million a year, starting at 86 million in 2010.
To find the year they are the same, set (A) = (B), and get
(1) -4x + 200 = 20x + 86 or
(2) 24x = 114 or
(C) x = 4 and 9/12 years
They will be equal on October 1, 2014.