Question

Which of the following linear equations describes that relationship?

O A. f(x) = x + 3
B. f(x) = 3x - 1
C. f(x) = 2x + 1
O D. f(x) = 4x - 3

Answer 1

• D. f(x) = 4x - 3

Explanation:

Use two pairs of points to work out the equation:

• (1, 1) and (2, 5)

Find the slope:

• m = (5 - 1) / (2 - 1) = 4/1 = 4

Find the y-intercept:

• 1 = 4*1 + b
• b = 1 - 4
• b = - 3

The line is:

• f(x) = 4x - 3

Correct choice is D