cho mik hỏi cách phân tích đa thưc sau: a2-5ax+6x2
phan tích hộ mik với
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\(a,a^2-2a-4b^2-4b\)
\(=\left(a^2-4b^2\right)-\left(2a+4b\right)\)
\(=\left(a-2b\right)\left(a+2b\right)-2\left(a+2b\right)\)
\(=\left(a+2b\right)\left(a-2b-2\right)\)
\(b,x^3-2x^2+4x-8\)
\(=x^2\left(x-2\right)+4\left(x-2\right)\)
\(=\left(x-2\right)\left(x^2+4\right)\)
\(c,x^3+36x-12x^2\)
\(=x^3-6x^2-6x^2+36x\)
\(=x^2\left(x-6\right)-6x\left(x-6\right)\)
\(=\left(x-6\right)\left(x^2-6x\right)\)
\(=x\left(x-6\right)^2\)
\(d,5a^2+3\left(a+b\right)^2-5b^2\)
\(=\left(5a^2-5b^2\right)+3\left(a+b\right)^2\)
\(=5\left(a^2-b^2\right)+3\left(a+b\right)^2\)
\(=5\left(a-b\right)\left(a+b\right)+3\left(a+b\right)^2\)
\(=\left(a+b\right)\left[5\left(a-b\right)+3\left(a+b\right)\right]\)
\(=\left(a+b\right)\left(5a-5b+3a+3b\right)\)
\(=\left(a+b\right)\left(8a-2b\right)\)
\(=2\left(a+b\right)\left(4a-b\right)\)
\(e,x^3-3x^2+3x-1-y^3\)
\(=\left(x^3-3x^2+3x-1\right)-y^3\)
\(=\left(x-1\right)^3-y^3\)
\(=\left(x-1-y\right)\left[\left(x-1\right)^2+\left(x-1\right)y+y^2\right]\)
\(=\left(x-y-1\right)\left(x^2-2x+1+xy-y+y^2\right)\)
\(=\left(x-y-1\right)\left(x^2+y^2-xy-y+1\right)\)
#Urushi☕
\(c.\\ x^3+36x-12x^2\\ =x\left(x^2-12x+36\right)\\ =x.\left(x^2-2.x.6+6^2\right)\\ =x.\left(x-6\right)^2\\ ---\\ d.\\ 5a^2+3\left(a+b\right)^2-5b^2\\ =\left(5a^2-5b^2\right)+3\left(a+b\right)^2\\ =5.\left(a^2-b^2\right)+3.\left(a+b\right)\left(a+b\right)\\ =5\left(a+b\right)\left(a-b\right)+3\left(a+b\right)\left(a+b\right)\\ =\left(a+b\right)\left(5a-5b+3a+3b\right)\\ =\left(a+b\right)\left(8a-2b\right)\\ =2\left(a+b\right)\left(4a-b\right)\)
\(e.\\ x^3-3x^2+3x-1-y^3\\ =\left(x-1\right)^3-y^3\\ =\left(x-1-y\right)\left[\left(x-1\right)^2+\left(x-1\right).y+y^2\right]\\ =\left(x-y-1\right).\left[\left(x^2-2x+1\right)+y\left(x+y-1\right)\right]\)
\(\left(x+2\right)\left(x+3\right)\left(x+4\right)\left(x+5\right)-8=\left(x^2+7x+10\right)\left(x^2+7x+12\right)-8\)
Đặt \(x^2+7x=t\)
\(\left(t+10\right)\left(t+12\right)-8=t^2+22t+120-8\)
\(=t^2+22t+112=\left(t+8\right)\left(t+14\right)\)
Theo cách đặt \(=\left(x^2+7x+8\right)\left(x^2+7x+14\right)\)
a: \(=5a\left(x-2y\right)\)
b: \(=x\left(x-y\right)+\left(x-y\right)=\left(x-y\right)\left(x+1\right)\)
c: =(x-1)(x-7)
a)\(5ax-10ay=5a\left(x-2y\right)\)
b) \(x^2-xy+x-y=x\left(x-y\right)+\left(x-y\right)=\left(x+1\right)\left(x-y\right)\)
c) \(x^2-8x+7=\left(x-7\right)\left(x-1\right)\)
Ta có:\(25x^2-y^2+6yz-9z^2=25x^2-\left(y-3z\right)^2=\left(5x+y-3z\right)\left(5x-y+3z\right)\)
\(25x^2-y+6yz-9z^2\)
\(=\left(5x\right)^2-\left(y^2-6yz+9z^2\right)\)
\(=\left(5x\right)^2-\left(y-3z\right)^2\)
\(=\left(5x-y+3z\right)\left(5x+y-3z\right)\)
Vậy \(25x^2-y^2+6yz-9z^2=\left(5x-y+3z\right)\left(5x+y-3z\right)\)
Cách để Phân tích nhân tử đa thức bậc ba: 12 Bước (kèm Ảnh) ( vô tkhđ )
A nghĩ ở đây mấy cách lớp 8 dùng được . Em tham khảo nha
ta có \(2x^2+3881x-17505=2x^2-9x+3890x-17505\)
\(=x\left(2x-9\right)+1945\left(2x-9\right)=\left(2x-9\right)\left(x+1945\right)\)
2x2+3881x-17505
= 2x2+3890x-9x-17505
=2x(x+1945)-9(x+1945)
=(x+1945)(2x-9)
Đúng thì k giúp mình nha
\(=x\left(x-1\right)+y\left(x-1\right)^2=\left(x-1\right)\left[x+y\left(x-1\right)\right]\\ =\left(x-1\right)\left(x+xy-y\right)\)
Ta có \(a^2-5ax+6x^2\)
\(=a^2-4ax+\left(2x\right)^2-ãx+2x^2\)
\(=\left(a^2+4ax+\left(2x\right)^2\right)-\left(ãx-2x^2\right)\)
\(=\left(a-2x\right)^2-x.\left(a-2x\right)\)
\(=\left(a-2x\right).\left(\left(a-2x\right)-x\right)\)
\(a^2-5ax+6x^2=a^2-2ax-3ax+6x^2=a\left(a-2x\right)-3x\left(a-2x\right)=\left(a-2x\right)\left(a-3x\right)\)