Toán Lớp 8: phân tích đa thức thành nhân tử
a (x^2+3x+1)(x^2+3x+2)-6x∧2
b (x-3)(x-5)(x-6)(x-10)-24x∧2
c (x+3)(x-1)(x-5)(x+15)+64x∧2
∧ ∧ ∧ ∧
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Toán Lớp 8: phân tích đa thức thành nhân tử
a (x^2+3x+1)(x^2+3x+2)-6x∧2
b (x-3)(x-5)(x-6)(x-10)-24x∧2
c (x+3)(x-1)(x-5)(x+15)+64x∧2
∧ ∧ ∧ ∧
Comments ( 2 )
Tui gửi
Giải +giải chi tiết
A,(x^2+3x+1)(x^2+3x+2)-6x^2
=x^4+3x^3+x^2+3x^3+9x^2+3x+2x^2+6x+2-6x^2
=x^4+6x^3+6x^2+9x+2
=2(1/2x^4+3x^3+2x^2+9/2x+1)
B,(x-3)(x-5)(x-6)(x-10)-24x^2
=(x^2-3x-5x+15)(x^2-6x-10x+60)-24x^2
=(x^2-8x+15)(x^2-16x+60)-24x^2
=x^4-8x^3+15x^2-16x^3+128x^2-240x+60x^2-480x+900
=x^4-24x^3+203x^2-920x+900
=24(1/24x^4-x^3+203/24x^2-920/24x+900/24)
C,(x+3)(x-1)(x-5)(x+15)+64x^2
=(x^2+3x-x-3)(x^2+15x-5x-75)+64x^2
=(x^2+2x-3)(x^2+10x-75)+64x^2
=x^4+10x^3-75x^2+2x^3+20x^2-150x-3x^2-30x+225
=x^4+12x^3+58x^2-180x+225
=12(1/12x^4+x^3+58/12x^2-15x+225/12)