y=f(x) is a linear function that gives the cost (in dollars) of having x square feet of a certain type of carpet installed in your home. 300 square feet cost $650 while 500 square feet cost $950.
Find a formula for y= f(x)
2007-09-04 02:06:48 · 3 answers · asked by Ask or Answer 2 in Science & Mathematics ➔ Mathematics
y=ax+b
650= 300a+b
950= 500a+b
300 =200a so a= 3/2
650-450=200= b
y= 3/2x+200
2007-09-04 02:19:32 · answer #1 · answered by santmann2002 7 · 0⤊ 0⤋
You have 2 points on the line. (300,650) and (500,950)
The change in cost as sq. footage changes is therefore
(950-650) / (500-300), =300/200, or 3/2. This is "m". My formula looks like this, so far.
y=f(x)=3/2 x+b (This from the slope-intercept equation for any linear function, y=mx+b)
Now,(300,650) lies on the line. If I substitute 300 for x and 650 for y in my equation, I can find b
650=3/2(300)+b
650=450+b
200=b
My formula is y=(3/2)x+200
2007-09-04 11:51:55 · answer #2 · answered by Grampedo 7 · 0⤊ 0⤋
y = 1.5x + 200
2007-09-04 09:19:57 · answer #3 · answered by raja 2 · 0⤊ 0⤋