linear function

Question

suppose that f is a linear function with slope -3.6 and that f(3)=8. what value of x gives f(x)=0? round answer to two decimal places

Answer 1

Start with point-slope form

(y - 8) = -3.6(x - 3)

y - 8 = -3.6x + 10.8

y = -3.6x + 18.8

Answer 2

We will need the equation of the line. We have the slope, but we also need the y-intercept.

The f(3) = 8 means when x is 3, y = 8. so (3,8) are the coordinates of one of the points on the line.

Let's use y = mx + b and substitute the given information.

8 = (-3.6)(3) + b

b = 18.8

The equation of the line is y = -3.6x + 18.8

The question is find the value of x for when f(x) = 0. We are asked to find the value of x so that the value of y will be 0.

Using the equation we found, substitute 0 for y and solve for x.