Final answer:
The correct translation is "Tengo que explicar un problema de matemáticas a mi amigo."
Step-by-step explanation:
The correct translation of "I have to explain a math problem to my friend" in Spanish is:
Tengo que explicar un problema de matemáticas a mi amigo.
In this sentence, the verb "explicar" means "to explain" and the phrase "un problema de matemáticas" means "a math problem." The phrase "a mi amigo" means "to my friend." So, altogether the sentence means "I have to explain a math problem to my friend."
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