Question

Tìm x:

a. \(\dfrac{5}{7}+\dfrac{4}{5}-x=\dfrac{9}{7}\)

b. \(x\text{×}\dfrac{7}{12}+\dfrac{4}{3}=\dfrac{9}{5}\)

Answer 1

\(a)\dfrac{5}{7}+\dfrac{4}{5}-x=\dfrac{9}{7}\)

\(\dfrac{4}{5}-x=\dfrac{9}{7}-\dfrac{5}{7}\)

\(\dfrac{4}{5}-x=\dfrac{4}{7}\)

\(x=\dfrac{4}{5}-\dfrac{4}{7}\)

\(x=\dfrac{8}{35}\)

\(b)x.\dfrac{7}{12}+\dfrac{4}{3}=\dfrac{9}{5}\)

\(x.\dfrac{7}{12}=\dfrac{9}{5}-\dfrac{4}{3}\)

\(x.\dfrac{7}{12}=\dfrac{7}{15}\)

\(x=\dfrac{7}{15}:\dfrac{7}{12}\)

\(x=49\)

Answer 2

a) 5/7 + 4/5 - x = 9/7

53/35 - x = 9/7

x = 53/35 - 9/7

x = 8/35

b) x × 7/12 + 4/3 = 9/5

x × 7/12 = 9/5 - 4/3

x × 7/12 = 7/12

x = 7/15 : 7/12

x = 4/5