Đáp án: D

65− 4 x + 2 = 2020 0

65− 4 x + 2 =1

4 x + 2 =65-1

4 x + 2 =64

4 x + 2 =43

x + 2 =3

x =3 - 2

x =1

2.GTLN:4

1.x=-5

x = 1 và x = 3

xin lỗi chị nha! em mới học lớp 6 thôi. nên em chỉ cho chị đáp số thôi nhé!x=227

\(\left|2x-1\right|=\dfrac{3}{2}\\ \Rightarrow\left[{}\begin{matrix}2x-1=\dfrac{3}{2}\\2x-1=-\dfrac{3}{2}\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=\dfrac{5}{4}\\x=-\dfrac{1}{4}\end{matrix}\right.\)

Thay \(x=\dfrac{5}{4}\) vào D ta có:

\(D=4x+3=4.\dfrac{5}{4}+3=5+3=8\)

Thay \(x=-\dfrac{1}{4}\) vào D ta có:

\(D=4.\dfrac{-1}{4}+3=-1+3=2\)

Để \(D=\dfrac{3}{2}\)

\(\Leftrightarrow4x+3=\dfrac{3}{2}\\ \Leftrightarrow4x=-\dfrac{3}{2}\\ \Leftrightarrow x=-\dfrac{3}{8}\)

\(\left|2x-1\right|=\dfrac{3}{2}\)

\(\Leftrightarrow\left[{}\begin{matrix}2x-1=\dfrac{3}{2}\\2x-1=\dfrac{-3}{2}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}2x=\dfrac{5}{2}\\2x=\dfrac{-1}{2}\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{5}{4}\\x=\dfrac{-1}{4}\end{matrix}\right.\)

\(x=\dfrac{5}{4}\text{ thì }D=4.\dfrac{5}{4}+3=5+3=8\)

\(x=\dfrac{-1}{4}\text{ thì }D=4.\left(\dfrac{-1}{4}\right)+3=\left(-1\right)+3=2\)

\(D=\dfrac{-5}{2}\Leftrightarrow4x+3=\dfrac{-5}{2}\)

               \(\Leftrightarrow4x=\dfrac{-11}{2}\)

               \(\Leftrightarrow x=\dfrac{-11}{8}\)