We need help . we think we got it but were not sure

13.5/3= 4.5 4.5x10= 450 The original price is 450 dollars
4.5=10%
315= 70%
You paid 315 dollars

What you do is subsitute the first number in the pair for x and subsitute the second number for f(x)

you must have made a typing error when typing the options since they are alll correct
proabably one of the two (7,23) is mistyped

basically one example is the point (0,9)
x=0
f(x)=9
subsitute
9=2(0)+9
9=0+9
9=9
this is true so it is a soltuion

the answer choice is not listed (probably because of a typo)