Question

[Nguyễn Phan Thùy Anh]

1. Thực hiện phép tính:

a) -4,3.y -1/2.y -3/4= -0,4

b) 4.( y-1/3)³ =0

c) 13 - 2. /1 -2y/ =1

2. Thực hiện phép tính

a) 22/7 : (-10/7) -7/3

b) 28/7 : 14 / 3 - 2.( -1/13)

c) 31/4 : 0,5 + 7/4 : ( -0,5)

Answer 1

[lê thị hương giang]

1.Thực hiện phép tính :

a) -4,3y - \(\frac{1}{2}y-\frac{3}{4}=-0,4\)

=> (-4,3- \(\frac{1}{2}\))y = -0,4 + \(\frac{3}{4}\)

=> \(\frac{-24}{5}\)y = \(\frac{7}{20}\)

=> y = \(\frac{7}{20}:\frac{-24}{5}\)

=> y = \(\frac{-7}{96}\)

b) 4\(\left(y-\frac{1}{3}\right)^3=0\)

=> y³ - \(\frac{1}{3}^3\) = 0

=> y³ - \(\frac{1}{27}=0\)

=> y³ = \(\frac{1}{27}\)

=> y = \(\frac{1}{3}\)

c) 13 -2 . | 1 - 2y | = 1

=> 2.| 1 - 2y | = 13 - 1

=> 2.| 1 - 2y | = 12

=> | 1 - 2y | = 6

=> \(\left[\begin{matrix}1-2y=6\\1-2y=-6\end{matrix}\right.\)

=> \(\left[\begin{matrix}2y=-5\\2y=7\end{matrix}\right.\)

=> \(\left[\begin{matrix}y=\frac{-5}{2}\\y=\frac{7}{2}\end{matrix}\right.\)

Answer 2

[Vũ Mạnh Chí]

Bài 1:

a)\(\frac{-4}{3}.y.\frac{-1}{2}.y.\frac{-3}{4}=-0.4\)

\(\Leftrightarrow\frac{-4}{3}.\frac{-3}{4}.\frac{-1}{2}.y^2=\frac{-2}{5}\)

\(\Leftrightarrow\frac{-1}{2}y^2=\frac{-2}{5}\)

\(\Leftrightarrow y^2=\frac{4}{5}\)

\(\Leftrightarrow\left[\begin{matrix}y=\sqrt{\frac{4}{5}}\\y=-\sqrt{\frac{4}{5}}\end{matrix}\right.\)

b) \(4.\left(y-\frac{1}{3}\right)^3=0\)

\(\Leftrightarrow\left(y-\frac{1}{3}\right)^3=0\)

\(\Leftrightarrow y-\frac{1}{3}=0\)

\(\Leftrightarrow y=\frac{1}{3}\)

c) 13-2.|1-2y|=1

<=>2.|2y-1|=12

<=>|2y-1|=6

<=> \(\left[\begin{matrix}2y-1=6\\2y-1=-6\end{matrix}\right.\)

<=>\(\left[\begin{matrix}y=3,5\\y=-2,5\end{matrix}\right.\)