Hvordan multipliserer du polynomene (x ^ 2 + 2x - 1) (x ^ 2 + 2x + 5)?

Hvordan multipliserer du polynomene (x ^ 2 + 2x - 1) (x ^ 2 + 2x + 5)?
Anonim

Svar:

# X ^ 4 + 4x ^ 3 + 6x ^ 2 + 8x-5 #

Forklaring:

Bare bruk en modifisert versjon av folie eller et bord

# X ^ 2 (x ^ 2 + 2x + 5) = x ^ 4 + 2x ^ 3 + 5x ^ 2 #

# 2 x (x ^ 2 + 2x + 5) = 2x ^ 3 + 2x ^ 2 + 10x #

# -1 (x ^ 2 + 2x + 5) = - x ^ 2-2x-5 #

Bare legg dem opp

# X ^ 4 + 2x ^ 3 + 5x ^ 2 + 2x ^ 3 + 2x ^ 2 + 10 x-x ^ 2-2x-5 #

# X ^ 4 + farger (rød) (2x ^ 3 + 2x ^ 3) + farge (blå) (5x ^ 2 + 2x ^ 2 x ^ 2) + farge (rosa) (10x-2x) -5 #

# X ^ 4 + farger (rød) (4x ^ 3) + farge (blå) (6x ^ 2) + farge (rosa) (8x) -5 #

Svar:

# X ^ 4 + 4x ^ 3 + 8x ^ 2 + 8x-5 #

Forklaring:

gitt-

# (X ^ 2 + 2x-1) (x ^ 2 + 2x + 5) #

# (x ^ 2 xx x ^ 2) + (2x xx x ^ 2) - (1 xxx ^ 2) + (x ^ 2xx 2x) + (2x xx 2x) - (1 xx 2x) + (x ^ 2 xx5) + (2x xx5) - (1xx5) #

# X ^ 4 + 2x ^ 3-x ^ 2 + 2x ^ 3 + 4x ^ 2-2x + 5x ^ 2 + 10x-5 #

# X ^ 4 + 2x ^ 3 + 2x ^ 3-x ^ 2 + 4x ^ 2 + 5x ^ 2-2x + 10x-5 #

# X ^ 4 + 4x ^ 3 + 8x ^ 2 + 8x-5 #