Question

calcule :
a) (x+2).(x-1).(x+3)
b) (x³-2).(x³+8)
c) (x²+2).(x²+6)

Answer 1

$a) \\ \\ (x + 2) * (x - 1) * (x + 3) \\ \\ (x^2 -x + 2x - 2) * (x + 3) \\ \\ (x^2 + x - 2)*(x + 3) \\ \\ x^3 + 3x^2 + x^2 + 3x - 2x -6 \\ \\ => x^3 + 4x^2 + x - 6$

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$b) \\ \\ (x^3 - 2) * (x^3 + 8) \\ \\ x^6 + 8x^3 - 2x^3 - 16 \\ \\ => x^6 + 6x^3 - 16$

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$c) \\ \\ (x^2 + 2) * (x^2 + 6) \\ \\ x^4 + 6x^2 + 2x^2 + 12 \\ \\ => x^4 + 8x^2 + 12$