13.2.1 Graphs of Functions, PT3 Focus Practice
Question 1:
In the figure shown, when x = 4, the value of y is
Solution:
T is the point on the graph where x = 4.
Hence, when x = 4, y = 5.
Question 2:
Diagram shows the graph of a function on a Cartesian plane.
The equation that represents the function is
Solution:
Use points (0, 6) and (3, 0) to determine the function.
Function

Value of y when


x = 0

x = –3


y = x + 3

3

0

y = x – 3

–3

–6

y = 2x + 6

6

0 (correct)

y = 2x – 6

–6

–12

Question 3:
Table below shows the values of variables x and y of a function.
x

–2

0

1

y

–6

2

3

Which of the following functions is satisfied by the ordered pair?
A y = 7x + 2
B y = x^{3} + 2
C y = x + x^{2 }– 2
D y = x^{2} + 2
Solution:
Only y = x^{3} + 2 is satisfied by all the ordered pairs.
(i) –6 = (–2)^{3} + 2
(ii) 2 = 0^{3} + 2
(iii) 3 = 1^{3} + 2
Answer = B