Question

Giải phương trình:

(x^2 - 2.x + 1) - 2.(x-1) + 1 = 0

(x-3).(x+4)=(x-3).(x+5)

Answer 1

tự kết luận nhé 

a,\(\left(x^2-2x+1\right)-2\left(x-1\right)+1=0\)

\(\Leftrightarrow\left(x-1\right)^2-2\left(x-1\right)+1=0\)

\(\Leftrightarrow\left(x-1-1\right)^2=0\Leftrightarrow\left(x-2\right)^2=0\Leftrightarrow x=2\)

b, \(\left(x-3\right)\left(x+4\right)=\left(x-3\right)\left(x+5\right)\)

\(\Leftrightarrow\left(x-3\right)\left(x+4\right)-\left(x-3\right)\left(x+5\right)=0\)

\(\Leftrightarrow\left(x-3\right)\left(x+4-x-5\right)=0\Leftrightarrow x-3=0\Leftrightarrow x=3\)

\(x+4-x-5\ne0\Leftrightarrow0x\ne1\)

Answer 2

a) \(\left(x^2-2x+1\right)-2\left(x-1\right)+1=0\)

\(\Leftrightarrow\left(x-1\right)^2-2\left(x-1\right)+1=0\)

\(\Leftrightarrow\left(x-2\right)^2=0\)

\(\Leftrightarrow x-2=0\)

\(\Rightarrow x=2\)

b) \(\left(x-3\right)\left(x+4\right)=\left(x-3\right)\left(x+5\right)\)

\(\Leftrightarrow x-3=0\)

\(\Rightarrow x=3\)