Question

Tìm x, biết

e) (x-3)² -( x-2)(x+2)= -5

Answer 1

\(\left(x-3\right)^2-\left(x-2\right)\left(x+2\right)=-5\)

\(\Leftrightarrow x^2-6x+9-x^2+2x=-5\)

\(\Leftrightarrow13-6x=-5\)

\(\Leftrightarrow6x=13-\left(-5\right)\)

\(\Leftrightarrow6x=18\)

\(\Leftrightarrow x=18:6\)

\(\Leftrightarrow x=3\)

Answer 2

\(\left(x-3\right)^2-\left(x-2\right)\left(x+2\right)=-5\)

\(\Leftrightarrow x^2-6x+9-x^2+4=5\)

\(\Leftrightarrow-6x+13=5\)

\(\Leftrightarrow6x=18\)

=> x=3