Question

The graph of a linear function f passes through the point (-1,9) and has a slope of -3. what is the zero of f?

Answer 1

Answer:

Answer: x=2 (third option)

Step-by-step explanation:

Equation of a line

Being m is the slope and (h,k) is a point through which the line passes, the point-slope form of the equation of a line is:

y - k = m ( x - h )

We have the function f passes through the point (-1,9) and has a slope of m=-3. The point-slope equation of the line is:

y - 9 = -3 ( x - (-1) )

Operating:

y - 9 = -3 ( x + 1 )

y - 9 = -3x - 3

Adding 9:

y = -3x + 6

To calculate the zero of the function we set y=0 and solve for x:

-3x + 6 = 0

Subtracting 6:

-3x = - 6

Dividing by -3

x = - 6 / ( - 3 )

x = 2

Answer: x=2 (third option)