A/\(4x^2-12+9\)
\(=\left(2x\right)^2-2.2.3+3^2\)
\(=\left(2x+3\right)^2\)
B/\(11x+11y-x^2-xy\)
\(=\left(11x-x^2\right)+\left(11y-xy\right)\)
\(=x\left(11-x\right)+y\left(11-x\right)\)
\(=\left(11-x\right)\left(x+y\right)\)
C/\(4a^2b^2-\left(a^2+b^2-c^2\right)^2\)
\(=\left(2ab\right)^2-\left(a^2+b^2-c^2\right)^2\)
\(=\left(2ab+a^2+b^2-c^2\right)\left(2ab-a^2-b^2+c^2\right)\)
a, \(4x^2-12x+9=4x^2-6x-6x+9\)
\(=2x\left(2x-3\right)-3\left(2x-3\right)\)
\(=\left(2x-3\right)\left(2x-3\right)=\left(2x-3\right)^2\)
b, \(11x+11y-x^2-xy=x\left(11-x\right)+y\left(11-x\right)\)
\(=\left(11-x\right)\left(x+y\right)\)
c,\(4a^2b^2-\left(a^2+b^2-c^2\right)^2=\left(2ab+a^2+b^2-c^2\right)\left(2ab-a^2-b^2+c^2\right)\)
\(=\left[\left(a+b\right)^2-c^2\right]\left[c^2-\left(a-b\right)^2\right]\)
\(=\left(a+b-c\right)\left(a+b+c\right)\left(c-a+b\right)\left(c+a-b\right)\)
Ở câu A mik làm sai ạ
A/\(4x^2-12x+9\)
\(=\left(2x\right)^2-2.2.3.x+3^2\)
\(=\left(2x-3\right)^2\)
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