Question

Answer 1

\(a,x.\dfrac{-3}{4}=\dfrac{2}{5}+\dfrac{4}{5}\\ x.\dfrac{-3}{4}=\dfrac{6}{5}\\ x=\dfrac{-8}{5}\\ b,\dfrac{1}{5}x+\dfrac{4}{5}x+x=20\\ \left(\dfrac{1}{5}+\dfrac{4}{5}+1\right)x=20\\ 2x=20\\ x=10\\ c,\dfrac{-6}{7}-\dfrac{9}{10}x=\dfrac{24}{35}\\ \dfrac{9}{10}x=-\dfrac{54}{35}\\ x=-\dfrac{12}{7}\)