Simplify. (x3 + 2x − 3)(x4 − 3x2 + x) (please provide a step-by-step explanation and answer. I don't just need the answer I need to understand how to do this)

x12 − 3x6 − x4 + x3 + 3x2 − x
x12 − 3x6 − x4 + x3 − 15x2 − x
x7 − x5 − 2x4 − 6x3 + 11x2 − 3x
x7 − 5x5 − 2x4 − 6x3 + 11x2 − 3x

Lance lived in portugal and brazil for a total of 14 months to learn portuguese. he learned an average of 130 new words per month when he lived in portugal, and an average of 150 new words per month when he lived in brazil. in total he learned 1920 new words. write a system of equations to represent the situation. use x to represent portugal, and y to represent brazil

Ling listed all of the factors of a mystery number: 1,2,4,8,16,32 what is the mystery number?

Maurice has 54 fewer comic books than rebecca. they have 130 comic books together .how many comic books are in maurices collection ? how many comic books are in rebeccas collection