Answer:
1. Compound
2. Simple
3. Compound-Complex
Explanation:
Compound sentences are those that link two independent clauses, usually with a coordinating conjunction (FANBOYS: for, and, nor, but, or, yet, and so). Simple sentences just have one subject and one verb. Complex sentences are usually made up of an independent clause and a dependent clause. Compound-complex are those that are both compound and complex.
(Note that independent clauses are sentences that can stand-alone and are grammatically and literally correct; eg. <em>I went to the store</em>. Dependent clauses are sentences that cannot stand alone because they're missing either a subject or a verb; eg. <em>because he ran</em>.)
1. "They were out of tacos, and my brother was still hungry."
We see that the first clause "They were out of tacos" is independent because it can stand alone, and the second clause "my brother was still hungry" is also independent. They are linked by "and", which is a coordinating conjunction, so this is a compound sentence.
2. "We hurried to another restaurant to buy food."
There is a simple subject, "we", and a simple verb "hurried". Since there are no different clauses - just one - this is a simple sentence.
3. "After we got more food for my brother, he was happy, and I knew we would need to plan ahead of our next meal."
Notice that we have the dependent clause "After we got more food for my brother"; the two independent clauses "he was happy" and "I knew we would need to plan ahead of our next meal"; and a coordinating conjunction "and". Thus, this is compound-complex.
Hope this helps!