Đáp án: `a,` `x =` $\dfrac{339}{304}$.
`b,` `x =` $\dfrac{1}{2}$
Giải thích các bước giải:
Tìm `x`:
`a,` $\dfrac{7}{4}$ `- x ×` $\dfrac{4}{3}$ `=` $\dfrac{5}{19}$
`x ×` $\dfrac{4}{3}$ `=` $\dfrac{7}{4}$ `-` $\dfrac{5}{19}$
`x ×` $\dfrac{4}{3}$ `=` $\dfrac{113}{76}$
`x =` $\dfrac{113}{76}$ `:` $\dfrac{4}{3}$
`x =` $\dfrac{339}{304}$
Vậy `x =` $\dfrac{339}{304}$.
`b,` `x ×` $\dfrac{1}{2}$ `+` $\frac{3}{2}$ `× x` = $\dfrac{4}{4}$
`x ×` $\dfrac{1}{2}$ + $\dfrac{3}{2}$ `× x = 1`
`x ×` ( $\dfrac{1}{2}$ + $\dfrac{3}{2}$ ) `= 1`
`x × 2 = 1`
`x = 1 ÷ 2`
`x =` $\dfrac{1}{2}$
Vậy `x =` $\dfrac{1}{2}$.
