Presumably what these mean is "x *reduced by* 74.24%", that is, "x - 74.24% of x". You should never write that as"x - 74.24%", which is misleading.

Some calculators (for business applications?) have % keys that handle percent increase and decrease problems using a notation like x - 74.24%, but you would have to read the manual to be sure how it works, especially if you want to "undo" a percent increase, as in your problems. I avoid percent keys, both because calculators are inconsistent so I can't be sure what will happen, and because the notation they use is bad mathematically, leading to confusion for algebra students.

To solve it yourself, write the equation x - 0.7424x = 12.65 and solve for x, as Otis explained well.