Indicative + que + subjunctive help

[PieMage]

I'm doing an online assignment, and the program is not very helpful at pointing out what I'm doing wrong. Here are the instructions:
React to the following circumstances by completing the sentences according to the cues. Make any necessary changes. Remember that an infinitive phrase is generally used when there is no change of subject.I'll give the prompts and responses that I got wrong, any help would be greatly appreciated. I think the main thing I'm confused about is when to use que in the sentence and when not to.2) Es absurdo: las entradas (tickets) / espectáculo / costar / tanto dinero
Es absurdo que las entradas para el espectáculo cuete tanto dinero.3) Es increíble: (tú) no / conocer / novelas / Gabriel García Márquez
Es increíble que no conozca las novelas de Gabriel García Márquez.4) Sentimos: (nosotros) no / poder / ayudarlos a Uds.
Sentimos no poder ayduarlos a Uds.5) Me molesta: haber / tanto / personas / que / hablar / durante / función
Me molesta que hay tantas personas que hable durante el función.

[Rusty]

2) Es absurdo: las entradas (tickets) / espectáculo / costar / tanto dinero
Es absurdo que las entradas para el espectáculo cuete tanto dinero. The highlighted verb contains a typo and doesn't agree in number with the subject in the subordinate clause. The use of 'que' and casting the verb in the subjunctive are correct.
3) Es increíble: (tú) no / conocer / novelas / Gabriel García Márquez
Es increíble que no conozca las novelas de Gabriel García Márquez. The verb doesn't agree in person with the subject of the subordinate clause. The sentence is fine, otherwise.
4) Sentimos: (nosotros) no / poder / ayudarlos a Uds.
Sentimos no poder ayduarlos a Uds. Typo. Everything else is correct, but some will argue in favor of using a subordinate clause. Try it that way if correcting the typo isn't the "problem."
5) Me molesta: haber / tanto / personas / que / hablar / durante / función
Me molesta que hay tantas personas que hable durante el función. Subjunctive must be used for the first verb. The second verb doesn't agree in number with the subject. The article doesn't agree with its object.Hints given above.
Welcome to the forums!!

[PieMage]

Thank you so much for such an informative answer! I'm still strugling on #5, this is my current answer:

Me molesta que haya tantas personas que hablen durante la función.

Any advice?

[Rusty]

Your sentence looks good to me.
If your program doesn't like it, the third clause could be cast in the indicative mood. It all depends on what the author of the exercise had in mind at the time of writing.

[PieMage]

...the third clause could be cast in the indicative mood.

That's exactly what it was, thanks!

[Rusty]

¡No hay de qué!

I moved your other question to its own thread.