Usage of 'check out'

[Daemon99]

I went to the showroom to check out if there are any new cars in the market.

Can someone please tell me if the above sentence is correct?
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Non-native speaker of English
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I intend to live forever - so far, so good.

[Jamie (K)]

I would say "to check whether there are" or "to check and see if there are", or just "to see if there are".

"To check out if" doesn't sound right.

[Daemon99]

Thanks a lot, Jamie!

English is getting tougher for me everyday :( There are many such expressions I have been wrongly using with if structure. For example,

Can you please confirm if there are any more changes required?

I learnt that the above sentence is wrong too. Can you think of any more such expressions?
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Non-native speaker of English
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I intend to live forever - so far, so good.

[Jamie (K)]

It may be wrong, but plenty of native speakers say it, and I may have used it too. You can correct it just by changing "if" to "whether".

[Kitosdad]

Whether there were any new cars.
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Keep it simple ... Keep it interesting.