Here's an example...
So, in our last example...
In the point ( -2, -1 ), x1 = -2 and y1 = -1 ... and, in the point ( 4, 3 ), x2 = 3 and y2 = 3
m = ( y2 - y1 ) / ( x2 - x1 ) = ( 3 - ( -1 ) ) / ( 4 - ( -2 ) ) = 4 / 6 = 2 / 3
But, notice something cool...
The order of the points doesn't matter! Let's switch them and see what we get:
In the point ( 4, 3 ), x1 = 4 and y1 = 3 ... and, in the point ( -2, -1 ), x2 = -2 and y2 = -1
m = ( y2 - y1 ) / ( x2 - x1 ) = ( -1 - 3 ) / ( -2 - 4 ) = -4 / -6 = 2 / 3 ... Same thing!
Let's try our new formula with the second example in the last lesson:
It was a line passing through
( -1, 4 ) and ( 2, -2 )
m = ( y2 - y1 ) / ( x2 - x1 ) = ( -2 - 4 ) / ( 2 - ( -1 ) ) = -6 / 3 = -2
Answer:
Step-by-step explanation:
To find a function's inverse, you first switch the x and y coordinates, and then solve for the new y. The same goes for finding an inverse's function. We have:
We will switch the x and y variables and then solve for the new y:
and
11x = y + 4 so
11x - 4 = y and
11x - 4 = f(x) which is choice C.
Let pc be pencils, and pn be pens. Then:
5pc+pn=250
pc+2pn=185
Then
10pc+2pn=500
pc+2pn=185
9pc=315
pc=35
pn=75
Pencils are 35 cents; pens are 75 cents
