Question

Tìm x, biết

a) ( x-5)² - x(x -6)= 5

Answer 1

\(\left(x-5\right)^2-x\left(x-6\right)=5\)

\(\Leftrightarrow x^2-10x+25-x^2+6x=5\)

\(\Leftrightarrow25-4x=5\)

\(\Leftrightarrow4x=25-5\)

\(\Leftrightarrow4x=20\)

\(\Leftrightarrow x=20:4\)

\(\Leftrightarrow x=5\)

Answer 2

\(\left(x-5\right)^2-x\left(x-6\right)=5\)

\(\Leftrightarrow x^2-10x+25-x^2+6x=5\)

\(\Leftrightarrow-4x+25=5\)

\(\Leftrightarrow4x=20\)

=> x =5

Vaayj x=5

Answer 3

a) ( x-5)² - x(x -6)= 5(hằng đẳng thức)

x²-10x+25-x²+6x=5

                - 4x+25=5  

                       -4x=5-25

                       -4x=-20

                          x=(-20):(-4)

                          x=5