1) Tim x: a) x(x+1) +3(x+1) = 0 b) 3x(12x-4) - 2x(18x+3) =...
Đọc tiếp
1) Tim x: a) x(x+1) +3(x+1) = 0 b) 3x(12x-4) - 2x(18x+3) = 36
\(x.\left(x+1\right)+3.\left(x+1\right)=0\)
\(\left(x+1\right)\left(x+3\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x+1=0\\x+3=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=-1\\x=-3\end{cases}}}\)
Vậy \(\orbr{\begin{cases}x=-1\\x=-3\end{cases}}\)
\(3x\left(12x-4\right)-2x\left(18x+3\right)=36\)
\(36x^2-12x-36x^2-6x=36\)
\(-18x=36\)
\(\Rightarrow x=-2\)
Vậy \(x=-2\)
Tham khảo nhé~