Question

Please help. i need part b on 66, 68 and 70!

Answer 1

Step-by-step explanation:

Use the function to find the coordinates of the endpoints.  Find the slope between those points, then use point-slope form to write the equation.  If you wish, you can simplify to slope-intercept form.

For example, #66:

f(2) = -4(2) + 1 = -7

f(5) = -4(5) + 1 = -19

So the endpoints of the secant line are (2, -7) and (5, -19).  The slope between those lines is:

m = (-19 − (-7)) / (5 − 2)

m = -12 / 3

m = -4

The equation of the line in point-slope form is:

y − (-7) = -4 (x − 2)

y + 7 = -4 (x − 2)

Simplifying:

y + 7 = -4x + 8

y = -4x + 1

f(x) is a line, so unsurprisingly, the secant line connecting two points on that line has the same equation.

Let's try #68:

g(2) = (-1)² + 1 = 2

g(5) = (2)² + 1 = 5

So the endpoints of the secant line are (-1, 2) and (2, 5).  The slope between those lines is:

m = (5 − 2) / (2 − (-1))

m = 3 / 3

m = 1

The equation of the line in point-slope form is:

y − 2 = 1 (x − (-1))

y − 2 = x + 1

Simplifying:

y = x + 3