Phân tích đa thức thành nhân tử a)25x²-70xy+49y²
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\(=y\left(4x^2-4xy+y^2-49\right)\)
\(=y\left[\left(2x-y\right)^2-49\right]\)
\(=y\left(2x-y-7\right)\left(2x-y+7\right)\)
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a) Ta có: \(4x^2-28xy+49y^2\)
\(=\left(2x\right)^2-2\cdot2x\cdot7y+\left(7y\right)^2\)
\(=\left(2x-7y\right)^2\)
b) Ta có: \(x^2+8xy+16y^2\)
\(=x^2+2\cdot x\cdot4y+\left(4y\right)^2\)
\(=\left(x+4y\right)^2\)
c) Ta có: \(x^2-12x+36\)
\(=x^2-2\cdot x\cdot6+6^2\)
\(=\left(x-6\right)^2\)
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\(\left(25x^2-2\right)=\left(5x-\sqrt[]{2}\right)\left(5x+\sqrt[]{2}\right)\)
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A=12x2-16x-9x+12
A=4x(3x-4)-3(3x-4)
A=(3x-4)(4x-3)
dễ mà, tick nha
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\(25x^2-4y^2-4y-1\)
\(=25x^2-\left(2y+1\right)^2=\left(5x-2y-1\right)\left(5x+2y+1\right)\)
25x2 - 4y2 - 4y - 1
= 25x2 - (4y2 + 4y + 1)
= (5x)2 - (2y + 1)2
= [5x - (2y + 1)][5x + (2y + 1)]
= (5x - 2y - 1)(5x + 2y + 1)
\(25x^2-70xy+49y^2\\ =25x^2-35xy-35xy+49y^2\\ =25x\left(x-\dfrac{7}{5}y\right)-35y\left(x-\dfrac{7}{5}y\right)\\ =\left(25x-35y\right)\left(x-\dfrac{7}{5}y\right)\\ =5\left(5x-7y\right)\left(x-\dfrac{7}{5}y\right)\)
(5x-7y)^2