`a)`\(\dfrac{x+81}{19}+\dfrac{x+82}{18}=\dfrac{x+84}{16}+\dfrac{x+85}{15}\)
\(\Rightarrow\)\(\dfrac{x+81}{19}+1+\dfrac{x+82}{18}+1=\dfrac{x+84}{16}+1+\dfrac{x+85}{15}+1\)
`=>`\(\dfrac{x+81+19}{19}+\dfrac{x+82+18}{18}+\dfrac{x+84+16}{16}+\dfrac{x+85+15}{15}\)
`=>`\(\dfrac{x+100}{19}+\dfrac{x+100}{18}-\dfrac{x+100}{16}-\dfrac{x+100}{15}=0\)
`=>`\(\left(x+100\right)\left(\dfrac{1}{19}+\dfrac{1}{18}-\dfrac{1}{17}-\dfrac{1}{16}\right)=0\)
`=>x+100=0`
`=>x=-100`
Vậy `x=-100`
`b)`\(\dfrac{x+7}{3}+\dfrac{x+5}{4}=\dfrac{x+3}{5}+\dfrac{x+1}{6}\)
`=>`\(\dfrac{x+7}{3}+2+\dfrac{x+5}{4}+2=\dfrac{x+3}{5}+2+\dfrac{x+1}{6}+2\)
`=>`\(\dfrac{x+7+6}{3}+\dfrac{x+5+8}{4}=\dfrac{x+3+10}{5}+\dfrac{x+1+12}{6}\)
`=>`\(\dfrac{x+13}{3}+\dfrac{x+13}{4}-\dfrac{x+13}{5}-\dfrac{x+13}{6}=0\)
`=>`\(\left(x+13\right)\left(\dfrac{1}{3}+\dfrac{1}{4}-\dfrac{1}{5}-\dfrac{1}{6}\right)=0\)
`=>x+13=0`
`=>x=-13`
Vậy `x=-13`
a: =>(x+81/19+1)+(x+82/18)+1=(x+84/16+1)+(x+85/15+1)
=>x+100=0
hay x=-100
b: \(\Leftrightarrow\left(\dfrac{x+7}{3}+2\right)+\left(\dfrac{x+5}{4}+2\right)=\left(\dfrac{x+3}{5}+2\right)+\left(\dfrac{x+1}{6}+2\right)\)
=>x+13=0
hay x=-13
a.
PTTĐ:
\(\dfrac{x+81}{19}+1+\dfrac{x+82}{18}+1=\dfrac{x+84}{16}+1+\dfrac{x+85}{15}+1\)
\(\Leftrightarrow\dfrac{x+81}{19}+\dfrac{19}{19}+\dfrac{x+82}{18}+\dfrac{18}{18}=\dfrac{x+84}{16}+\dfrac{16}{16}+\dfrac{x+85}{15}+\dfrac{15}{15}\)
\(\Leftrightarrow\dfrac{x+81+19}{19}+\dfrac{x+82+18}{18}=\dfrac{x+84+16}{16}+\dfrac{x+85+15}{15}\)
\(\Leftrightarrow\dfrac{x+100}{19}+\dfrac{x+100}{18}=\dfrac{x+100}{16}+\dfrac{x+100}{15}\)
\(\Leftrightarrow\dfrac{x+100}{19}+\dfrac{x+100}{18}-\dfrac{x+100}{16}-\dfrac{x+100}{15}=0\)
\(\Leftrightarrow\left(x+100\right)\left(\dfrac{1}{19}+\dfrac{1}{18}-\dfrac{1}{16}-\dfrac{1}{15}\right)=0\)
\(\Rightarrow x+100=0\)
\(\Rightarrow x=-100\)
b.
PTTĐ:
\(\dfrac{x+7}{3}+2+\dfrac{x+5}{4}+2=\dfrac{x+3}{5}+2+\dfrac{x+1}{6}+2\)
em làm i hệt câu a là ra nha, cách làm i hệt nhé.
