Question

Which point lies on the graph of the following piecewise function?
y = x – 1 if x < 2
y = x^2 if x greater than or equal to 2

a.(1, 1)

b.(2, 1)

c.(–1, 1)

d.(3, 9)

Answer 1

d.

y = x^2 since x =3
y = 3^2
y = 9 , thus the point (3,9) is on the graph

Answer 2

isn't (2, 1) also on the graph?

Answer 3

For point (2,1) you have to use y = x^2, you don't use y = x -1. This is because x = 2 and tells you which function to use.

Answer 4

Ok, but why wouldnt you use y = x - 1, don't you use both?

Answer 5

No, you only use y = x-1 when x < 2. Not when it is actually x =2.

You can only use one equation per value of x.