How do we pass maths​

Which expression is equivalent to (4 +6i)^2? ? -20 + 48i 8 + 12i 16 - 36i 20 + 48i

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You’re ordering more thread for blue jeans co. you usually purchase from ted’s threads, which sells 12 thread spools for $27. you recently received a notice from wade's wares that says you can buy thread from them for $2.30 each for the first 2 dozen and $2 a spool thereafter. you need to order 5 dozen spools. what percentage can you save by going with wade’s wares?