Question

25x² -y² +4y-4

x+2y-xy-2

a²+b²-x²-y²+2ab-2xy

giup minh that nhanh voi

Answer 1

a) \(25x^2-y^2+4y-4\)

\(=\left(5x\right)^2-\left(y-2\right)^2\)

\(=\left(5x-y+2\right)\left(5x+y-2\right)\)

Answer 2

b) \(x+2y-xy-2\)

\(=\left(x-xy\right)+\left(2y-2\right)\)

\(=x\left(1-y\right)+2\left(y-1\right)\)

\(=x\left(1-y\right)-2\left(1-y\right)\)

\(=\left(1-y\right)\left(x-2\right)\)

Answer 3

c) \(a^2+b^2-x^2-y^2+2ab-2xy\)

\(=\left(a^2+b^2+2ab\right)-\left(x^2+2xy+y^2\right)\)

\(=\left(a+b\right)^2-\left(x+y\right)^2\)

\(=\left(a+b-x-y\right)\left(a+b+x+y\right)\)

Answer 4

a,\(25x^2-y^2+4y-4=25x^2-\left(y-2\right)^2=\left(5x-y+2\right)\left(5x+y-2\right)\)

b,\(x+2y-xy-2=x\left(1-y\right)-2\left(1-y\right)=\left(x-2\right)\left(1-y\right)\)

c,\(a^2+b^2-x^2-y^2+2ab-2xy=\left(a^2+2ab+b^2\right)-\left(x^2+2xy+y^2\right)\)

\(=\left(a+b\right)^2-\left(x+y\right)^2=\left(a+b+x+y\right)\left(a+b-x-y\right)\)

------------------------------------------------------------__________________________________________Tích giùm mk nha