Câu hỏi của Đan Chi Nguyễn

Question

$a$)$\dfrac{2}{5}.x-1=-4x$$b$) $3.\left(\dfrac{1}{2}x-1\right)=-x+1$$c$) $4^x+4^x+3+4$

Vũ Châu Anh · Accepted Answer

a) $\dfrac{2}{5}.x-1=-4x$     $-1=-4x-\dfrac{2}{5}.x\$     $x.\left(-4-\dfrac{2}{5}\right)=-1$     $x.\dfrac{-22}{5}=-1$     $x=-1:\dfrac{-22}{5}$     $x=\dfrac{5}{22}$ Câu trả lời: a) $\dfrac{2}{5}.x-1=-4x$     $-1=-4x-\dfrac{2}{5}.x\$     $x.\left(-4-\dfrac{2}{5}\right)=-1$     $x.\dfrac{-22}{5}=-1$     $x=-1:\dfrac{-22}{5}$     $x=\dfrac{5}{22}$

Vũ Châu Anh · Answer

b) $3.\left(\dfrac{1}{2}x-1\right)=-x+1$    $3.\dfrac{1}{2}x-3=-x+1$    $-3=-x+1-3.\dfrac{1}{2}x$    $x.\left(-1\right)+1-3.\dfrac{1}{2}x=-3$    $x.\left(-1-3.\dfrac{1}{2}\right)+1=-3$    $x.\dfrac{-5}{2}+1=-3$    $x.\dfrac{-5}{2}=-3-1$    $x.\dfrac{-5}{2}=-4$    $x=-4:\left(\dfrac{-5}{2}\right)$    $x=\dfrac{8}{5}$Câu trả lời: b) $3.\left(\dfrac{1}{2}x-1\right)=-x+1$    $3.\dfrac{1}{2}x-3=-x+1$    $-3=-x+1-3.\dfrac{1}{2}x$    $x.\left(-1\right)+1-3.\dfrac{1}{2}x=-3$    $x.\left(-1-3.\dfrac{1}{2}\right)+1=-3$    $x.\dfrac{-5}{2}+1=-3$    $x.\dfrac{-5}{2}=-3-1$    $x.\dfrac{-5}{2}=-4$    $x=-4:\left(\dfrac{-5}{2}\right)$    $x=\dfrac{8}{5}$

Bài 3: Nhân, chia số hữu tỉ

Khoá học trên OLM (olm.vn)

Khoá học trên OLM (olm.vn)