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a)\(\dfrac{3x^2-12x+12}{x^4-8x}=\dfrac{3\left(x^2-4x+4\right)}{x\left(x^3-8\right)}=\dfrac{3\left(x-2\right)^2}{x\left(x^3-2^3\right)}=\dfrac{3\left(x-2\right)^2}{x\left(x-2\right)\left(x^2+2x+4\right)}=\dfrac{3\left(x-2\right)}{x\left(x^2+2x+4\right)}\)
25n(n-1)-50(n-1) luôn chia hết cho 150 với mọi n là số nguyên
giúp mình chứng minh nha . Cám ơn mấy bạn
= 2x^2 + 2x +5x+5
=(2x^2+2x)+(5x+5)
=2x(x+1)+5(x+1)
=(x+1)(2x+5)
\(\Rightarrow3x^2-10x+3x-10\)
\(\Rightarrow x\left(3x-10\right)+\left(3x-10\right)\)
\(\Rightarrow\left(3x-10\right)\left(x+1\right)\)
T I C K nha cảm ơn rất nhìu
\(15x^2+7x-2\)
\(=15x^2+10-3x-2\)
\(=5x\left(3x+2\right)-\left(3x+2\right)\)
\(=\left(3x+2\right)\left(5x-1\right)\)
\(7x-3x^2-2\)
\(=6x+x-3x^2-2\)
\(=\left(6x-3x^2\right)+\left(x-2\right)\)
\(=-3x\left(x-2\right)+\left(x-2\right)\)
\(=\left(-3x+1\right)\left(x-2\right)\)
\(7x - 3x^2 - 2\)
\(= 6x + x - 3x^2 - 2\)
\(=(6x-3x^2)+(x-2)\)
\(= -3x(x-2)+(x-2)\)
\(=(-3x+1)(x-2)\)
a, \(x^4+6x^3+7x^2-6x+1\)
\(=x^4-2x^2+1+6x^3+9x^2+6x\)
\(=\left(x^2-1\right)^2+6x\left(x^2-1\right)+9x^2\)
\(=\left(x^2-1+3x\right)^2\)
b, \(x^4-7x^3+14x^2-7x+1\)
\(=x^4+2x^2+1+7x^3+12x^2-7x\)
\(=\left(x^2+1\right)^2-7x\left(x^2+1\right)+12^2\)
\(=\left(x^2-1+3x\right)^2\)
c, \(12x^2-11x-36\)
\(=12x^2-27x+16x-36\)
\(=3x\left(4x-9\right)+4\left(4x-9\right)\)
\(=\left(4x-9\right)\left(3x+4\right)\)
\(x^2+7x+12\)
cách 1: \(=x^2+4x+3x+12\)
\(=x\left(x+4\right)+3\left(x+4\right)\)
\(=\left(x+4\right)\left(x+3\right)\)
cách 2: \(=x^2+3x+4x+12\)
\(=x\left(x+3\right)+4\left(x+3\right)\)
\(=\left(x+3\right)\left(x+4\right)\)
cách 3: \(=\left(x^2+7x+12,25\right)-0.25\)
\(=\left(x+3.5\right)^2-0.5^2\)
\(=\left(x+3.5+0.5\right)\left(x+3.5-0.5\right)\)
\(=\left(x+4\right)\left(x+3\right)\)
lấy đâu ra 8 cách vậy trời!!!!!!!!!!!!!!!
Cách 1:
\(x^2+7x+12\)
\(=\left(x^2+4x\right)+\left(3x+12\right)\)
\(=x\left(x+4\right)+3\left(x+4\right)\)
\(=\left(x+3\right)\left(x+4\right)\)