Question

tim x biet : x^2+7x+10=0

Answer 1

(X+2)(X+5)=0

=>x=-2 hoặc x=-5

Answer 2

x^2+7x+10=0

x(x+7)=-10

=>x>0                 x<0

    x+7<0             x+7<0

Mà x+7>x

=>x<0      =>x<0

    x+7>0      x>-7

=>x thuộc -1;-2;-3;-4;-5;-6

Answer 3

\(x^2+7x+10=0\)

\(x^2+2x+5x+10=0\)

\(x\left(x+2\right)+5\left(x+2\right)=0\)

\(\left(x+2\right)\left(x+5\right)=0\)

\(\Rightarrow\orbr{\begin{cases}x+2=0\\x+5=0\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=-2\\x=-5\end{cases}}\)