X = 0

Y = 6

4 x X + X x Y + y

= 4 x 0 + 0 x 6 + 6

= 0 + 0 + 6

= 6

X = 0

Y = 6

4 x X + X x Y + y

= 4 x 0 + 0 x 6 + 6

= 0 + 0 + 6

= 6

\(x:0,2+x:0,125-x\cdot3=78\)

\(=>x:\left(0,2:0,125\cdot3\right)=78\)

\(=>x:4,8=78\)

\(=>x=374,4\)

\(\cdot\)là nhân nha

ti ck mik cầu xin đó

####

\(x:0,2+x:0,125-x3=78\)

\(x.5+x.8-x.3=78\)

\(x\left(5+8-3\right)=78\)

\(x.10=78\)

\(\Leftrightarrow x=7,8\)

Mik nói thật nhé lũ CTV OLM n g u như c a k ấy

Ủa vậy you zô đây chi

<=> 10x-9,9=0,1.x+9,9

<=> 100x-99=x+99

<=> 99x=99+99

<=> 99x=198  => x=198:99 => x=2

Đáp số: x=2

Mik nói thật nhé lũ CTV OLM n g u như c a k ấy

\(a,\left(x+\frac{1}{2}\right)+\left(x+\frac{1}{4}\right)+\left(x+\frac{1}{8}\right)+\left(x+\frac{1}{16}\right)=1\)

\(\Leftrightarrow x+\frac{1}{2}+x+\frac{1}{4}+x+\frac{1}{8}+x+\frac{1}{16}=1\)

\(\Leftrightarrow\left(x+x+x+x\right)+\left(\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}\right)=1\)

\(\Leftrightarrow4\times x+\frac{15}{16}=1\)

\(\Leftrightarrow4\times x=1-\frac{15}{16}\)

\(\Leftrightarrow4\times x=\frac{1}{16}\)

\(\Leftrightarrow x=\frac{1}{16}\div4\)

\(\Leftrightarrow x=\frac{1}{64}\)

\(b,x-\frac{20}{11.13}-\frac{20}{13.15}-...-\frac{20}{53.55}=\frac{3}{11}\)

\(\Leftrightarrow x-\left(\frac{20}{11.13}+\frac{20}{13.15}+...+\frac{20}{53.55}\right)=\frac{3}{11}\)

\(\Leftrightarrow x-\left[715\times\left(\frac{1}{11}-\frac{1}{13}-\frac{1}{13}+...+\frac{1}{55}\right)\right]=\frac{3}{11}\)

\(\Leftrightarrow x-\left[715\times\left(\frac{1}{11}-\frac{1}{55}\right)\right]=\frac{3}{11}\)

\(\Leftrightarrow x-\left[715\times\frac{4}{55}\right]=\frac{3}{11}\)

\(\Leftrightarrow x-52=\frac{3}{11}\)

\(\Leftrightarrow x=\frac{3}{11}+52\)

\(\Leftrightarrow x=\frac{575}{11}\)

giúp mk với nha

\(\dfrac{1}{1\cdot2}+\dfrac{1}{2\cdot3}+\dfrac{1}{3\cdot4}+.......+\dfrac{1}{x\cdot\left(x+1\right)}=\dfrac{122}{123}\)

\(\Leftrightarrow1-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{4}+......+\dfrac{1}{x}-\dfrac{1}{x+1}=\dfrac{122}{123}\)

\(\Leftrightarrow1-\dfrac{1}{x+1}=\dfrac{122}{123}\)

\(\Leftrightarrow\dfrac{1}{x+1}=\dfrac{1}{123}\)

\(\Leftrightarrow x=122\)

đây là toán lớp 5 mà có cả kí hiệu toán lớp 8 rồi giỏi ghê