# Thread: how do you find the equation of a secant???

1. ## how do you find the equation of a secant???

Given the curve F(x)=x^2-3x+7. If A is the point where x=3 and B is the point where x=5, find the equation of the secant AB.

2. Originally Posted by deej813
Given the curve F(x)=x^2-3x+7. If A is the point where x=3 and B is the point where x=5, find the equation of the secant AB.
Can you find the equation of a line that passes through the points (3,7) and (5,17)?

3. yeah
i got the gradient as 5
then the equation using the y-y1=m(x-x1)
as 5x-y-8=0
but the answer says 7x-2y-1=0
what did i do wrong??

4. Originally Posted by deej813
yeah
i got the gradient as 5
then the equation using the y-y1=m(x-x1)
as 5x-y-8=0
but the answer says 7x-2y-1=0
what did i do wrong??
The work is right, but either the function you posted is incorrect, or one (or both) of the A and B values are incorrect.

5. ok well they are all right so maybe the answer is just wrong
thanks heaps