Question

Function A and Function B are linear functions.
Function A
x y
–
6
–
20
2 4
4 10
Function B
y=4x–1

Answer 1

From the table, Function A has points (−6, −20), (2, 4), (4, 10).

Slope of A: m = (10 − 4)/(4 − 2) = 6/2 = 3 (you can check (4 − (−20))/(2 − (−6)) = 24/8 = 3 also).

So A: y = 3x + b. Use (2,4): 4 = 3·2 + b → b = −2. Therefore Function A is
y = 3x − 2.

Function B is y = 4x − 1.

Intersection: solve 3x − 2 = 4x − 1 → x = −1. Then y = 3(−1) − 2 = −5.
So they intersect at (−1, −5).

Note: B has slope 4, A slope 3, so B is steeper. Would you like a graph of these?