(a-b)(a+b) because when you reverse the sum you do axa and ax-b xx
M<1+ m<2 = 90
-2x + 54 + 8x + 18 = 90
6x + 72 = 90
6x = 90 - 72
6x = 18
x = 3
(5 + i)(4 - 2i)
20 - 10i + 4i - 2i²
20 - 6i - 2(-1)
20 - 6i + 2
20 + 2 - 6i
22 - 6i
Divide -22 by -0.4 and you’ll have your answer for k