SOLUTION: Here's another one! Please help! suppose that the population of Country A is given by y=-6.95x + 903.74 million and the population of Country B is given by y= 2.45x + 743.94 milli

Algebra ->  College  -> Linear Algebra -> SOLUTION: Here's another one! Please help! suppose that the population of Country A is given by y=-6.95x + 903.74 million and the population of Country B is given by y= 2.45x + 743.94 milli      Log On


   

Question 872604: Here's another one! Please help!
suppose that the population of Country A is given by y=-6.95x + 903.74 million and the population of Country B is given by y= 2.45x + 743.94 million. Where X is the number of years since 1960. Find the year in which the population of the country's were equal. Explain the method you used to find your answer
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
If the populations are equal then y is same in both equations.
solve both equations
6.950 x + 1.000 y = 903.740 .............1

-2.450 x + 1.000 y = 743.940 .............2
Eliminate y
multiply (1)by -1.000
Multiply (2) by 1.000
-6.950 x -1.000 y = -903.740
-2.450 x + 1.000 y = 743.940
Add the two equations
-9.400 x = -159.800
/ -9.400
x = 17 years
1960 +17 = 1977 they were equal