Answer:
f(x) = 4x
Step-by-step explanation:
Verification:
f(2) = 4 x 2 = 8
f(3) = 4 x 3= 12
f(4) = 4x x 4 = 16
P C
3 39
4 48
5 57
6 66
9(3)=27+12=39=c
9(4)=36+12=48=c
57=9p+12
-12 -12
45=9p
divide by 9 both sides 45/9=5=p
c=9(6)+12
c=54+12
c=66
-12x/-4=-27
+4 +4
-12x=-23
-------------
-12
X=0.52
41/33 should be added to -15/33 (which is the same number as -5/11 but converted to have same denominator).
So answer is 41/33
Multiply 15%*9.99=1.4985 this is the discount.
If you substract 9.99-1.4985= $8.4915 this is the sale price.