BECE Mathematics 2018 Paper

Try each of the rules by substituting the values of x to see if you could get the corresponding y values.
The rule which gives all the corresponding values of y is the correct rule.
Rule: y⟶‌

x

2

−2
When x=0
‌

0

2

−2=0−2=−2
When x=3
‌

3

2

−2=1.5−2=−0.5
Not the rule.
Rule: y⟶x−2
When x=0
0−2=−2
When x=3
3−2=1
Not the rule.
Rule: y⟶x2−2
When x=0
02−2=−2
When x=3
32−2=9−2=7
Not the rule.
Since all the three options are not, automatically the fourth is the rule but you can still verify.
Rule: y⟶2x−2
When x=0
2(0)−2=0−2=−2
When x=3
2(3)−2=6−2=4
When x=6
2(6)−2=12−2=10
When x=9
2(9)−2=18−2=16
When x=12
2(12)−2=24−2=22
y⟶2x−2 is the rule.