It's a simultaneous equation:
Steps:
1.Number the equations..
a+b=77 -1
a-b=13 -2
2. Choose what variable you want to use. In this case I would use the "b". Since the signs in front of the "b's" are different, add the two equations together
a + b = 77
+ + +
a (-b) = 13
Which gives;
2a = 90
Then solve to find a:
2a=90
a= 90/2
a=45
3.Then plug the "a" value into any of the original equations to find the "b" value. I would use equation 1 since the all the variables are positive.
a + b = 77
(45) + b = 77
b=77-45
b=32
4.Solution
a=45
b=32
Answer: 895 phones
Step-by-step explanation:
Given that :
The function : y = 1.28e^1.31x ; is used to model the number of camera phones shipped since 1997
y = number of camera phones ; x = number of years since 1997
The number of camera phones shipped in the year 2002 can be obtained thus ;
x = 2002 - 1997 = 5 years
y = 1.28e^(1.31 * 5)
y = 1.28e^6.55
y = 1.28(699.24417)
y = 895.03254
y = 895 phones
