a, \(\dfrac{4x}{7}=\dfrac{1}{5}+\dfrac{2}{3}=\dfrac{3+10}{15}=\dfrac{13}{15}\Rightarrow60x=91\Leftrightarrow x=\dfrac{91}{60}\)

b, \(\dfrac{5}{7}:x=\dfrac{1}{6}+\dfrac{4}{5}=\dfrac{5+24}{30}=\dfrac{29}{30}\Leftrightarrow x=\dfrac{5}{7}:\dfrac{29}{30}=\dfrac{150}{203}\)

\(x\times\dfrac{3}{5}=\dfrac{2}{3}+\dfrac{1}{6}=\dfrac{5}{6}\)

\(x=\dfrac{5}{6}:\dfrac{3}{5}=\dfrac{25}{18}\)

X x 3/5 = 5/6
X          = 5/6 : 3/5
X          = 25/18

\(x\times\dfrac{3}{5}=\dfrac{2}{3}+\dfrac{1}{6}\)

\(x\times\dfrac{3}{5}=\dfrac{4}{6}+\dfrac{1}{6}\)

\(x\times\dfrac{3}{5}=\dfrac{5}{6}\)

\(x=\dfrac{5}{6}:\dfrac{3}{5}\)

\(x=\dfrac{5}{6}\times\dfrac{5}{3}\)

\(x=\dfrac{25}{18}\)

Ta có: \(\left(x^{3n}+y^{3n}\right)\left(x^{3n}-y^{3n}\right)=-x^6-y^6\)

\(\Leftrightarrow x^{6n}-y^{6n}=-x^6-y^6\)

\(\Leftrightarrow\left\{{}\begin{matrix}n=-1\\n=1\end{matrix}\right.\Leftrightarrow n\in\varnothing\)

a) 6/-x=x/-24

=> -x.x=6.-24

=>-x.x=-144

=>x=12 hay x=-12

b)9/x=-35/105

=>9/x=-1/3

=>x=9.3/-1=-27

=>x=-27

c)x-1/8=5/8

=>x=5/8+1/8

=>x=3/4

d)x-1/2-(3/2+x)=-2

=>-x+4/2=-2

=>-x/2=0

=>x=0

e)x+1/3=-12/5.10/6

x+1/3=-4

x=-4-1/3

x= -13/3

#YM

hai phần nha

tớ chưa hiểu đề bài 

\(246:x+34:x=5\)
\(\Rightarrow\left(246+34\right):x=5\)
\(\Rightarrow280:x=5\)
\(\Rightarrow x=280:5=56\)

\(360:x-126:x=6\)
\(\Rightarrow\left(360-126\right):x=6\)
\(\Rightarrow234:x=6\)
\(\Rightarrow x=234:6=39\)

15/8−4/9×6/8+1/6=15/8−24/72+1/6=15/8−1/3+1/6

=45/24−8/24+4/24=(45−8+4)/24=41/24

\(\dfrac{15}{8}-\dfrac{4}{9}\times\dfrac{6}{8}+\dfrac{1}{6}=\dfrac{15}{8}-\dfrac{24}{72}+\dfrac{1}{6}=\dfrac{15}{8}-\dfrac{1}{3}+\dfrac{1}{6}=\dfrac{45}{24}-\dfrac{8}{24}+\dfrac{4}{24}=\dfrac{\left(45-8+4\right)}{24}=\dfrac{41}{24}\)

x²+5x+1=(x+5)\(\sqrt{x^2+1}\)

\(\Leftrightarrow x^2+5x+1=\left(x+5\right)\left(x+1\right)\)

\(\Leftrightarrow x^2+5x+1=x^2+x+5x+5\)

<=> -x=4

<=> x=-4

\(x=5\)

\(x=3\)

học tốt

a, 2x+3x-3=27-x

<=>5x-3=27-x

chuyển vế, ta có:

5x+x=27+3

<=>6x=30

<=> x=5

b, 4+8x-5x+10=23

14+3x=23

=> 3x=9

=> x=3

\(a,\left(2x+3\cdot\left(x-1\right)\right)-\left(27-x\right)=0.\)

\(6x-30=6\cdot\left(x-5\right)\)

\(6\cdot\left(x-5\right)=0\)

\(x-5=0\)

\(x=5\)

\(b,\left(\left(4\cdot\left(2x+1\right)\right)-5\cdot\left(x-2\right)\right)-23=0\)

\(3x-9=3\cdot\left(x-3\right)\)

\(3\cdot\left(x-3\right)=0\)

\(x-3=0\)

\(x=3\)