Answer:
The cost of tuition as a function of x, the number of years since 1990, is C(x)= 14*(x-1990) + 95
Step-by-step explanation:
A linear function is a polynomial function of the first degree that has the following form:
y= m*x + b
where
- m is the slope of the function
- n is the ordinate (at the origin) of the function
So, in this case: C(x)= m*( x-1990) + b where x is the number of years since 1990.
Given the coordinates of two points, it is possible to determine the slope m of the line from them using the following formula:
In this case, you know that in 1990, the cost of tuition at a large Midwestern university was $95 per credit hour. And in 1999, tuition had risen to $221 per credit hour. So:
- x1= 1990
- y1= 95
- x2= 1999
- y2= 221
So the value of m is:
m= 14
So C(x)= 14*( x-1990) + b. In 1999, tuition had risen to $221 per credit hour. Replacing:
221= 14*(1999 - 1990) + b
221= 14*9 +b
221= 126 + b
221 - 126= b
95= b
Finally, <u><em>the cost of tuition as a function of x, the number of years since 1990, is C(x)= 14*(x-1990) + 95</em></u>