\(\Leftrightarrow x+1,5x+3,5x=252\)

<=>6x=252

<=>x=42

ủng hộ nhe

thank you

a ) \(x+x\times\frac{1}{3}\div\frac{2}{9}+x\div\frac{2}{7}=252\)

\(x\times1+x\times\frac{1}{3}\div\frac{2}{9}+x\div\frac{2}{7}=252\)

\(x\times1+x\times\frac{1}{3}\times\frac{9}{2}+x\times\frac{7}{2}=252\)

\(x\times1+x\times\frac{9}{6}+x\times\frac{7}{2}=252\)

\(x\times\left(1+\frac{9}{6}+\frac{7}{2}\right)=252\)

\(x\times6=252\)

\(x=252\div6\)

\(x=42\)

b ) \(\left(3\times x-0,8\right)\div x+14,5=15\)

\(\left(3\times x-0,8\right)\div x=15-14,5\)

\(\left(3\times x-0,8\right)\div x=0,5\)

\(0,8\div x=3-0,5\)

\(0,8\div x=2,5\)

\(x=0,8\div2,5\)

\(x=0,32\)

\(x+x\times\frac{1}{3}:\frac{2}{9}+x:\frac{2}{7}=252\)

\(x+x\times\frac{3}{2}+x\times\frac{7}{2}=252\)

\(x\times\left(1+\frac{3}{2}+\frac{7}{2}\right)=252\)

\(x\times6=252\)

\(x=252:6\)

\(x=42\)

X + X x \(\frac{1}{3}\)x\(\frac{9}{2}\)+ X x\(\frac{7}{2}\)= 252

X + X x \(\frac{3}{2}\)+ X x \(\frac{7}{2}\)= 252

X x (\(\frac{3}{2}\)+ \(\frac{7}{2}\)+1) = 252

X x (\(\frac{3}{2}\)+ \(\frac{7}{2}\)+ \(\frac{2}{2}\)) = 252

X x 6 = 252

X = 252 : 6

X= 42

Chúc bạn học tốt! ^^

\(\frac{x+1}{9}+\frac{x+2}{8}+\frac{x+3}{7}+...+\frac{x+9}{1}=-9\)

\(\left(\frac{x+1}{9}+1\right)+\left(\frac{x+2}{8}+1\right)+\left(\frac{x+3}{7}+1\right)+...+\left(\frac{x+9}{1}+1\right)=0\)

\(\frac{x+10}{9}+\frac{x+10}{8}+\frac{x+10}{7}+...+\frac{x+10}{1}=0\)

\(\left(x+10\right).\left(\frac{1}{9}+\frac{1}{8}+\frac{1}{7}+...+1\right)=0\)

vì \(\frac{1}{9}+\frac{1}{8}+\frac{1}{7}+...+1\ne0\)

\(\Rightarrow x+10=0\)

\(\Rightarrow x=-10\)

SKT_NTT làm đúng ùi -_- 100 %

\(\left(\frac{x+1}{9}+1\right)+\left(\frac{x+2}{8}+1\right)+...+\left(\frac{x+9}{1}+1\right)=-9+9\)

\(\Rightarrow\frac{x+10}{9}+\frac{x+10}{8}+...+\frac{x+10}{1}\) =

<=>x.1+x.3/2+x.7/2=252

x.(1+3/2+7/2)=252

x.6=252

x=252:6

=>x=42

\(x+x\times3:\frac{2}{9}+x:\frac{2}{7}=252\)

\(x+x\times\left(3:\frac{2}{9}\right)+x\times\frac{7}{2}=252\)

\(x+x\times\frac{27}{2}+x\times\frac{7}{2}=252\)

\(x\times\left(1+\frac{27}{2}+\frac{7}{2}\right)=252\)

\(x\times18=252\)

\(x=14\)