Toán Lớp 8: phân tích các đa thức sau thành nhân tử
a: 6x^2y – 8xy^2 +12x^2y^2
b: 4x^2 – 4xy -7x + 7y
c: x^2 + 5x + 6
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Toán Lớp 8: phân tích các đa thức sau thành nhân tử
a: 6x^2y – 8xy^2 +12x^2y^2
b: 4x^2 – 4xy -7x + 7y
c: x^2 + 5x + 6
Comments ( 2 )
$\text{a) 6x²y – 8xy² + 12x²y²}$
$\text{= 2xy(3x – 4y + 6xy)}$
$\text{b) 4x² – 4xy – 7x + 7y}$
$\text{= (4x² – 4xy) – (7x – 7y)}$
$\text{= 4x(x – y) – 7(x – y)}$
$\text{= (x – y)(4x – 7)}$
$\text{c) x² + 5x + 6}$
$\text{= x² + 2x + 3x + 6}$
$\text{= x(x + 2) + 3(x + 2)}$
$\text{= (x + 2)(x + 3)}$
$\textit{Ha1zzz}$
a,
6.x^2y – 8.xy^2 +12.x^2y^2
=3.x.2.xy-4.y.2.xy+6.xy.2.xy
=2.xy.(3.x-4.x+6.xy)
b,
4.x^2 – 4.xy -7.x + 7.y
=(4.x^2-4.xy)-(7x-7y)
=(4.x.x-4.x.y)-(7.x-7.y)
=4.x(x-y)-7(x-y)
=(x-y).(4.x-7)
c,
x^2+5.x+6
=x^2+2.x+3.x+6
=(x^2+2.x)+(3.x+6)
=(x.x+2.x)+(3.x+3.2)
=x.(x+2)+3.(x+2)
=(x+2).(x+3)