Answer: 4/5 will reduce and 7/2 will enlarge.
Explanation:
Ok, a scale factor is a number that can affect a given quantity, suppose the length of a segment, by multiplicating it.
Now, if the scale factor is greater than one, you will be doing a dilatation (this means that the length is increased)
If the scale factor is less than one, you will be doing a contraction (the length will be decreased)
If the scale factor is 1, you are preserving, this means that the scale factor = 1 does not affect the system.
now, we have:
4/5) here, because the numerator is smaller than the denominator we know that the fraction 4/5 must be smaller than one, so this scale factor will reduce.
7/2) Here we have that the numerator is greater than the denominator, so this number is greater than one, then this scale factor will enlarge