a: \(\frac{5\left(x-1\right)+2}{6}-\frac{7x-1}{4}=\frac{2\left(2x+1\right)}{7}-5\)
=>\(\frac{5x-5+2}{6}-\frac{7x-1}{4}=\frac{2\left(2x+1\right)-35}{7}\)
=>\(\frac{2\left(5x-3\right)-3\left(7x-1\right)}{12}=\frac{4x+2-35}{7}\)
=>\(\frac{10x-6-21x+3}{12}=\frac{4x-33}{7}\)
=>12(4x-33)=7(-11x-3)
=>48x-396=-77x-21
=>125x=-21+396=375
=>x=3
b: \(x-\frac{3\left(x+30\right)}{15}-24\frac12=\frac{7x}{10}-\frac{3\left(10x+2\right)}{5}\)
=>\(\frac{30-6\left(x+30\right)}{30}-24,5=\frac{21x}{30}-\frac{18\left(10x+2\right)}{30}\)
=>\(\frac{30-6x-180}{30}-24,5=\frac{21x}{30}-\frac{180x+36}{30}\)
=>-6x-150-735=21x-180x-36
=>-6x-885=-159x-36
=>153x=-36+885=849
=>x=849/153=283/51
d: \(\frac{x+1}{3}+\frac{3\left(2x+1\right)}{4}=\frac{2x+3\left(x+1\right)}{6}+\frac{7+12x}{12}\)
=>\(\frac{4\left(x+1\right)+9\left(2x+1\right)}{12}=\frac{2\left(2x+3x+3\right)}{12}+\frac{12x+7}{12}\)
=>4(x+1)+9(2x+1)=2(5x+3)+12x+7
=>4x+4+18x+9=10x+6+12x+7
=>22x+13=22x+13
=>0x=0(luôn đúng)
=>x∈R
