There are a lot of math questions here. I'll do the first six questions (number 9 through 14) to get you started.
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Problem 9
[tex]4i(-2-8i)\\\\4i(-2)+4i(-8i)\\\\-8i-32i^2\\\\-8i-32(-1)\\\\-8i+32\\\\32-8i[/tex]
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Problem 10
[tex]5i*-i\\\\-5i^2\\\\-5(-1)\\\\5\\\\[/tex]
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Problem 11
[tex]5i*i*-2i\\\\-(5*2)i^2*i\\\\-10i^2*i\\\\-10(-1)*i\\\\10i\\\\[/tex]
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Problem 12
[tex]-4i*5i\\\\-20i^2\\\\-20(-1)\\\\20\\\\[/tex]
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Problem 13
[tex](-2-i)(4+i)\\\\x(4+i) \ \text{.... let x = -2-i}\\\\4x+xi\\\\4(x)+i(x)\\\\4(-2-i)+i(-2-i) \ \text{.... plug in x = -2-i}\\\\-8-4i-2i-i^2\\\\-8-6i-i^2\\\\-8-6i-(-1)\\\\-8-6i+1\\\\-7-6i\\\\[/tex]
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Problem 14
[tex](7-6i)(-8+3i)\\\\x(-8+3i) \ \text{.... let x = 7-6i}\\\\-8x+3xi\\\\-8(x)+3i(x)\\\\-8(7-6i)+3i(7-6i) \ \text{.... plug in x = 7-6i}\\\\-56+48i+21i-18i^2\\\\-56+69i-18(-1)\\\\-56+69i+18\\\\-38+69i\\\\[/tex]