Question

Không làm tắt

Answer 1

a) 2x²-3x=0

\(\Rightarrow\)x(2x-3)=0

\(\Rightarrow\)\(\left[{}\begin{matrix}x=0\\2x-3=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\2x=3\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x=\dfrac{3}{2}\end{matrix}\right.\)

Answer 2

c) (x+1)(x-2)-(x-3)²=x+1

⇒(x+1)(x-2)-(x-3)²-(x+1)=0

\(\Rightarrow\)x²-2x+x-2-(x²-6x+9)-x-1=0

⇒x²-2x+x-2-x²+6x-9-x-1=0

\(\Rightarrow\)4x-12=0

\(\Rightarrow\)4x=12

\(\Rightarrow\)x=3

Answer 3

d)(2x+3-x-1)(2x+3+x+1)=(x+2)(3x+4)=3x²+4x+6x+8=3x²+10x+8

Answer 4

e)x³-x²+x-1=0

\(\Rightarrow\)(x³-x²)+(x-1)=0

\(\Rightarrow\)x²(x-1)+(x-1)=0

\(\Rightarrow\)(x-1)(x²+1)=0

\(\Rightarrow\)x-1=0 hoặc x²+1=0

\(\Rightarrow\left[{}\begin{matrix}x-1=0\\x^2+1=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=1\\x^2=-1\left(KTĐTSx\right)\end{matrix}\right.\)

KTĐTSx: không tìm được thừa số x

Vậy S={1}