a)\(\left(x-\frac{-7}{8}\right)+2,3=3,24\)
\(x+\frac{7}{8}=3,24-2,3\)
\(x+\frac{7}{8}=0,94\)
\(x+0,875=0,94\)
\(x=0,94-0,875=0,065=\frac{13}{200}\). Vậy x=13/200
b)\(\left(x-\frac{1}{2}\right)\left(1+5x\right)=0\)
=> *)\(x-\frac{1}{2}=0\) hay 1+5x=0=> 5x=0-1=-1
\(x=0+\frac{1}{2}=\frac{1}{2}\) hay \(x=-\frac{1}{5}\)
Vậy x=1/2 hoặc s=-1/5
c)\(x\left(4,6+\frac{3}{5}\right)=7,2-8,15\)
\(x\cdot\left(\frac{23}{5}+\frac{3}{5}\right)=-0,95\)
\(x\cdot\frac{26}{5}=-0,95\)
\(x\cdot5,2=-0,95\)
\(x=-0,95:5,2=-0,182692307\)
mình nghĩ chắc đề câu c sai
d)\(2\cdot3^x\cdot3^2=18\)
\(2\cdot3^x\cdot9=18\)
\(3^x=18:9:2\)
\(3^x=1\)
=> x=0. Vậy x=0
Chúc bạn học tốt!^_^
