It's 6!
When you multiply both the numerator and denominator by the same number, you will have an equivalent to the fraction you started with because the new fraction can be reduced to the original fraction.
2/3 = 4/6 = 6/9 = 8/12 = 10/15 = 12/15 etc.
What do you need help with?
Ur output value is f(x).....so to do this problem u need to sub in 2/3 for f(x) and solve for the input value which is x
f(x) = -1/3x + 7
2/3 = -1/3x + 7 ...multiply everything by 3
2 = -x + 21
2 - 21 = - x
- 19 = -x
19 = x <== ur output
