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1. 2x=16\(\Rightarrow\)X=4
2. 22x-1=27
\(\Rightarrow\)27=22.4-1
Vậy x =4
a) \(-\frac{7}{2}:\left(3-x\right)-0,75=\frac{1}{4}\)
\(\Leftrightarrow\frac{-7}{2\left(3-x\right)}=\frac{1}{4}+0,75=0,25+0,75=1\)
\(\Leftrightarrow2\left(3-x\right)=-7\)
\(\Leftrightarrow3-x=-\frac{7}{2}\)
\(\Leftrightarrow x=3+\frac{7}{2}\)
\(\Leftrightarrow x=\frac{13}{2}\)
b) \(\left|2x-\frac{4}{3}\right|-1\frac{1}{3}=-\frac{8}{9}\)
\(\Leftrightarrow\left|2x-\frac{4}{3}\right|=\frac{4}{3}-\frac{8}{9}=\frac{4}{9}\)
\(\Leftrightarrow\orbr{\begin{cases}2x-\frac{4}{3}=\frac{4}{9}\\2x-\frac{4}{3}=-\frac{4}{9}\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}2x=\frac{4}{3}+\frac{4}{9}=\frac{16}{9}\\2x=\frac{4}{3}-\frac{4}{9}=\frac{8}{9}\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=\frac{8}{9}\\x=\frac{4}{9}\end{cases}}\)
-15 ( x - 2 ) + 7 ( 3 - x ) = 7
-15x + 30 + 21 - 7x = 7
-15x - 7x = 7 - 21 - 30
-22x = -44
x = ( -44 ) : ( -22)
x = 2
Vậy x = 2
-12 ( x - 5 ) + 7 ( 3 - x ) = 5
-12x + 60 + 21 - 7x = 5
-12x - 7x = 5 - 21 - 60
-19x = -76
x = ( -76 ) : (-19)
x = 4
Vậy x = 4.
# HOK TỐT #
a) \(x=\dfrac{-2}{7}+\dfrac{9}{7}=1\)
b) \(\dfrac{x}{3}=\dfrac{2}{5}+\dfrac{-4}{3}\)
\(\dfrac{x}{3}=\dfrac{-14}{15}\)
\(\Rightarrow x=\dfrac{3.-14}{15}=\dfrac{-14}{5}\)
\(x=\dfrac{-2}{7}+\dfrac{9}{7}\)
\(x=1\)
\(A=\frac{\left[\left(25-1\right):1+1\right]\left(25+1\right)}{2}=325.\)
\(B=\frac{\left[\left(51-3\right):2+1\right]\left(51+3\right)}{2}=675\)
\(C=\frac{\left[\left(81-1\right):4+1\right]\left(81+1\right)}{2}=861\)
I am not stupid
tớ ko thấy bài bạn ơi!