These are yes/no questions.

There are two types of journal entries complex and simple?
My answer is no, I believe there are more such as Special.

Trade discounts reduce transportation costs?
My answer, no. It as nothing to do with transportation. It's a discount on the quantity of merchandise sold.

Cash discounts taken are credited to inventory?
My answer, No. Confused

Cash discounts given are subtracted from sales?
My answer, Yes? Confused on this one

FIFO leaves the most recent costs in inventory?
My answer, No. I think LIFO leaves most recent cost in inventory.

There are two types of journal entries complex and simple?
My answer is no, I believe there are more such as Special.
Complex entries involve more than one account while simple entries have only one account for debit and credit. For example, assume you receive cash 980 from a customer against total dues of 1,000 and 20 represents cash discount. You debit cash 980 and sales discount 20 and credit accounts receivable 1,000. This is a complex entry.

Trade discounts reduce transportation costs?
My answer, no. It as nothing to do with transportation. It's a discount on the quantity of merchandise sold. - Correct

Cash discounts taken are credited to inventory?
My answer, No. Confused - Correct. These are adjusted from cost of purchases

Cash discounts given are subtracted from sales?
My answer, Yes? Confused on this one. Correct. You get the net sales. However, under the British system, sales discounts are treated as selling expenses

FIFO leaves the most recent costs in inventory?
My answer, No. I think LIFO leaves most recent cost in inventory. - Incorrect. Under FIFO, old prices are charged to issues and the inventory has the recent prices.

There are two types of journal entries complex and simple?
My answer is no, I believe there are more such as Special.
Complex entries involve more than one account while simple entries have only one account for debit and credit. For example, assume you receive cash 980 from a customer against total dues of 1,000 and 20 represents cash discount. You debit cash 980 and sales discount 20 and credit accounts receivable 1,000. This is a complex entry.

Trade discounts reduce transportation costs?
My answer, no. It as nothing to do with transportation. It's a discount on the quantity of merchandise sold. - Correct

Cash discounts taken are credited to inventory?
My answer, No. Confused - Correct. These are adjusted from cost of purchases

Cash discounts given are subtracted from sales?
My answer, Yes? Confused on this one. Correct. You get the net sales. However, under the British system, sales discounts are treated as selling expenses

FIFO leaves the most recent costs in inventory?
My answer, No. I think LIFO leaves most recent cost in inventory. - Incorrect. Under FIFO, old prices are charged to issues and the inventory has the recent prices.

Thank you!!

To the first question. Are there more than two types of journals or only two main types? So is the first question yes?

Complex journal entries as givrn in example is just one type. There can be more accounts affected for one transaction.

For example, consider a case where a non current asset is disposed for cash. In such a case you will:
Debit Cash
Debit Accumulated depreciaition
Credit Asset
and the difference will either be gain or loss on disposal. Gain will be credits and losses will be debited.

Another case is exchange of assets:
Debit asset with fair value of new asset
Debit Accumulated depreciation
Credit old asset
Credit Cash

The trade in allowance will then be adjusted against book value of asset to determine loss or gain on asset.