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a) \(\dfrac{ax+ay-bx-by}{ax-ay-bx+by}=\dfrac{a\left(x+y\right)-b\left(x+y\right)}{a\left(x-y\right)-b\left(x-y\right)}=\dfrac{\left(a-b\right)\left(x+y\right)}{\left(a-b\right)\left(x-y\right)}=\dfrac{x+y}{x-y}\)
b) \(\dfrac{a^2+b^2-c^2+2ab}{a^2-b^2+c^2+2ac}=\dfrac{\left(a+b\right)^2-c^2}{\left(a+c\right)^2-b^2}=\dfrac{\left(a+b+c\right)\left(a+b-c\right)}{\left(a+c+b\right)\left(a+c-b\right)}=\dfrac{a+b-c}{a+c-b}\)
\(=x\left(a-b\right)-\left(a^2-2ab+b^2\right)=\)
\(=\left(a-b\right)x-\left(a-b\right)^2=\)
\(=\left(a-b\right)\left[x-\left(a-b\right)\right]=\left(a-b\right)\left(x-a+b\right)\)
\(1)4x^2-25+\left(2x+7\right).\left(5.2x\right)\)
\(=\left(2x\right)^2-5^2-\left(2x+7\right).\left(2x-5\right)\)
\(=\left(2x.5\right)\left(2x+5\right).\left(2x+7\right)\left(2x-5\right)\)
\(=\left(2x-5\right)\left(2x+5-2x+7\right)\)
\(=\left(2x-5\right).12\)
\(2)3x+4-x^2-4x\)
\(=3(x+4)-\left(x+4\right)\)
\(=\left(3-x\right)\left(x+4\right)\)
\(3)5x^2-2y^2-10x+10y\)
\(=5\left(x^2-y^2\right)-10\left(x-4\right)\)
\(=5\left(x-y\right)\left(x+y\right)-10\left(x-y\right)\)
\(=\left(x-y\right)[5(x+y)-10]\)
Còn lại bn lm nốt nha!
a) \(a^2+b^2+2ab+2a+2b+1=\left(a^2+2ab+b^2\right)+\left(2a+2b\right)+1\)
\(=\left(a+b\right)^2+2\left(a+b\right)+1=\left[\left(a+b\right)+1\right]^2=\left(a+b+1\right)^2\)
b) K phân tích dc.
1)
\(x^2+4xy+4y^2-a^2+2ab-b^2\)
\(=(x^2+4xy+4y^2)-(a^2-2ab+b^2)\)
\(=(x+2y)^2-(a-b)^2\)
\(=(x+2y-a+b)(x+2y+a-b)\)
2)
\(m^2-6m+9-x^2+4xy-4y^2\)
\(=(m^2-6m+9)-(x^2-4xy+4y^2)\)
\(=(m-3)^2-(x-2y)^2\)
\(=[(m-3)-(x-2y)][(m-3)+(x-2y)]\)
\(=(m-3-x+2y)(m-3+x-2y)\)
3)
\(ax^2+bx^2+2axy+2bxy+ay^2+by^2\)
\(=a(x^2+y^2+2xy)+b(x^2+2xy+y^2)\)
\(=a(x+y)^2+b(x+y)^2\)
\(=(a+b)(x+y)^2\)
4)
\(ax^2+bx^2+6ax+6bx+9a+9b\)
\(=(ax^2+6ax+9a)+(bx^2+6bx+9b)\)
\(=a(x^2+6x+9)+b(x^2+6b+9)\)
\(=a(x+3)^2+b(x+3)^2=(a+b)(x+3)^2\)
5)
\(8a^2xy-18b^2xy\)
\(=2xy(a^2-9b^2)=2xy[a^2-(3b)^2]\)
\(=2xy(a-3b)(a+3b)\)