What is the units digit of the massive exponential expansion given by the expression: 7²⁰²⁶ + 3²⁰²⁶?

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Answer: A. 8

The units digits of powers of 7 and 3 repeat in cycles of 4. 2026 ÷ 4 leaves remainder 2.
7² ends in 9 and 3² ends in 9, so 7^2026 ends in 9 and 3^2026 ends in 9.
9 + 9 = 18, so the units digit is 8.

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What is the units digit of the massive exponential expansion given by the expression: 7²⁰²⁶ + 3²⁰²⁶?

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