Đáp án : $3$
D. $2(x - 1) + 3(x-2)-x - 4 = 0$
= $2 𝑥 − 2 + 3 ( 𝑥 − 2 ) − 𝑥 − 4 = 0$
= $2 𝑥 − 2 + 3 𝑥 − 6 − 𝑥 − 4 = 0$
= $2 𝑥 − 1 2 + 3 𝑥 − 𝑥 = 0$
= $4 𝑥 − 1 2 = 0$
= $4 𝑥 − 1 2 + 1 2 = 0 + 1 $
= $4x = 0 + 1 2$
= $4 𝑥 = 1 2$
= $\dfrac{4x}{4}$ = $\dfrac{12}{4}$
= $x = $ $\dfrac{12}{4}$
= $x =3$