Toán Lớp 8: Chia đa thức một biến đã sắp xếp
Làm tính chia
a) (4x^2-9y^2):(2x-3y)
b). (27x^3-1):(3x-1)
c) (8x^3+1):(4x^2-2x+1)
d) (x^2-3x+xy-3y):(x+y)
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Toán Lớp 8: Chia đa thức một biến đã sắp xếp
Làm tính chia
a) (4x^2-9y^2):(2x-3y)
b). (27x^3-1):(3x-1)
c) (8x^3+1):(4x^2-2x+1)
d) (x^2-3x+xy-3y):(x+y)
Comments ( 2 )
a) (4x^2 – 9y^2) : (2x – 3y)
= [(2x)^2 – (3y)^2] : (2x – 3y)
= (2x – 3y)(2x + 3y) : (2x – 3y)
= 2x + 3y
b) (27x^3 – 1) : (3x – 1)
= [(3x)^3 – 1] : (3x – 1)
= (3x – 1).[(3x)^2 + 3x.1 + 1^2] : (3x – 1)
= (3x – 1).(9x^2 + 3x + 1) : (3x – 1)
= 9x^2 + 3x + 1
c) (8x^3 + 1) : (4x^2 – 2x + 1)
= [(2x)^3 + 1] : (4x^2 – 2x + 1)
= (2x + 1).[(2x)^2 – 2x.1 + 1^2] : (4x^2 – 2x + 1)
= (2x + 1).(4x^2 – 2x + 1) : (4x^2 – 2x + 1)
= 2x + 1.
d) (x^2 – 3x + xy – 3y) : (x + y)
= [(x^2 – 3x) + (xy – 3y)] : (x + y)
= [x.(x – 3) + y.(x – 3)] : (x + y)
= (x + y).(x – 3) : (x + y)
= x – 3.
a)
(4x^2 – 9xy^2) : (2x-3y)
= [ (2x)^2 – (3x)^2] : (2x-3y)
= (2x+3y)(2x-3y) : (2x-3y)
= 2x + 3y
b)
(27x^3 -1) : (3x-1)
= [(3x)^3 – 1] : (3x-1)
= (3x-1)(9x^2 + 3x+1) : (3x-1)
= 9x^2 + 3x + 1
c)
(8x^3 + 1) : (4x^2 – 2x+1)
= [(2x)^3 + 1^3] :(4x^2-2x+1)
= (2x+1)(4x^2 – 2x+1) : (4x^2 – 2x+1)
= 2x+1
a)
(4x^2 – 9xy^2) : (2x-3y)
= [ (2x)^2 – (3x)^2] : (2x-3y)
= (2x+3y)(2x-3y) : (2x-3y)
= 2x + 3y
b)
(27x^3 -1) : (3x-1)
= [(3x)^3 – 1] : (3x-1)
= (3x-1)(9x^2 + 3x+1) : (3x-1)
= 9x^2 + 3x + 1
c)
(8x^3 + 1) : (4x^2 – 2x+1)
= [(2x)^3 + 1^3] :(4x^2-2x+1)
= (2x+1)(4x^2 – 2x+1) : (4x^2 – 2x+1)
= 2x+1
d)
(x^2 – 3x + xy – 3y) : (x+y)
= [ x (x-3) + y (x-3) ] :(x+y)
= (x+y)(x-3) : (x+y)