Question

tìm x, biết:

a) x= 7/25 + (-1)/5

b) x/2= (-5)/3 + 6/8

c) x/11= 5/11+4/-9

d) 5/9 + x/(-1)= -1/3

Answer 1

a: \(x=\dfrac{7}{25}+\dfrac{-1}{5}\)

=>\(x=\dfrac{7}{25}-\dfrac{5}{25}\)

=>\(x=\dfrac{2}{25}\)

b: \(\dfrac{x}{2}=\dfrac{-5}{3}+\dfrac{6}{8}\)

=>\(\dfrac{x}{2}=-\dfrac{5}{3}+\dfrac{3}{4}=\dfrac{-20}{12}+\dfrac{9}{12}=-\dfrac{11}{12}\)

=>\(x=-\dfrac{11}{12}\cdot2=-\dfrac{11}{6}\)

c: \(\dfrac{x}{11}=\dfrac{5}{11}+\dfrac{4}{-9}\)

=>\(\dfrac{x}{11}=\dfrac{-45}{99}+\dfrac{44}{99}=\dfrac{-1}{99}\)

=>\(x=-\dfrac{1}{99}\cdot11=-\dfrac{11}{99}=-\dfrac{1}{9}\)

d: Ta có: \(\dfrac{5}{9}+\dfrac{x}{-1}=-\dfrac{1}{3}\)

=>\(\dfrac{5}{9}-x=-\dfrac{1}{3}\)

=>\(x=\dfrac{5}{9}+\dfrac{1}{3}=\dfrac{8}{9}\)