1.
a) \(xy+y^2=y\left(x+y\right)\)
b) \(x^2+4xy+4y^2-25=\left(x+2y\right)^2-25=\left(x+2y-5\right)\left(x+2y+5\right)\)
c) \(x^2-y^2+2x+1=\left(x+1\right)^2-y^2=\left(x+1-y\right)\left(x+1+y\right)\)
tick cho mk nha
2.
a) \(x^2+x-6=0\)
\(\Delta=1^2-4.1.\left(-6\right)=25\)
\(x_1=-3;x_2=2\)
b) \(x\left(x-2\right)-5x+10=0\)
\(\Leftrightarrow x^2-7x+10=0\)
\(\Delta\left(-7\right)^2-4.1.10=9\)
\(x_1=2;x_2=5\)
c) \(\left(x+2\right)^2+\left(x+3\right)^2-2\left(x-1\right)\left(x+1\right)=9\)
\(\Leftrightarrow x^2+4x+4+x^2+6x+9-2x^2+2=9\)
\(\Leftrightarrow x^2+4x+4+x^2+6x-2x^2+2=0\)
\(\Leftrightarrow10x+6=0\)
\(\Leftrightarrow10x=-6\)
\(\Rightarrow x=-\dfrac{3}{5}\)
tick cho mk nha
