for this question i don't get why this is the answer isn't it just 0.42 x 0.17. for independent events you x them and disjoint you add them
I'm not sure what you mean by the last part. This probably hints at a much larger gap in your understanding that we're missing. The solution is correct because when you want to find the probability of either event happening, you add the probability of each individual event, then subtract one instance of them both happening to account for double counting. Note that the last step doesn't exist for disjoint events since that is always 0 in that case.
As for why isn't it just 0.42 x 0.17; that's just because it's not intersection. Union implies an OR relationship, intersection implies an AND. Be careful when interpreting the question.
for this question int it just 0.69+ 0.4
How can it be 0.69+0.4? The probability of anything cannot exceed 1. This should already be ringing alarm bells in your head and telling you that you cannot possibly be correct. Again, reread the solutions which are correct; try to deduce how they step through it at the very least (it will help a little bit). Similar idea to the first question again here.