Question

[Lê Phương Linh]

Tìm x, biết:

a) \(-\dfrac{3}{5}\) - x = -0,75

b) \(1\dfrac{4}{5}\) = -0,15 - x

c) \(2\dfrac{1}{2}\) - x +\(\dfrac{4}{5}\) = \(\dfrac{2}{3}\) - ( \(-\dfrac{4}{7}\))

Answer 1

[GV Nguyễn Trần Thành Đạt]

\(a,-\dfrac{3}{5}-x=-0,75\\ -\dfrac{3}{5}-x=-\dfrac{3}{4}\\ x=-\dfrac{3}{5}-\left(-\dfrac{3}{4}\right)\\ x=-\dfrac{3}{5}+\dfrac{3}{4}=\dfrac{3}{20}\\ ---\\ b,1\dfrac{4}{5}=-0,15-x\\ \dfrac{9}{5}=-\dfrac{3}{20}-x\\ x=-\dfrac{3}{20}-\dfrac{9}{5}\\ x=-\dfrac{3}{20}-\dfrac{36}{20}\\ x=-\dfrac{39}{20}\\ ----\\ c,2\dfrac{1}{2}-x+\dfrac{4}{5}=\dfrac{2}{3}-\left(-\dfrac{4}{7}\right)\\ \dfrac{5}{2}-x+\dfrac{4}{5}=\dfrac{2}{3}+\dfrac{4}{7}\\ \dfrac{33}{10}-x=\dfrac{26}{21}\\ x=\dfrac{33}{10}-\dfrac{26}{21}\\ x=\dfrac{433}{210}\)