Bài 1 Thực hiện phép tính
a) B = 50% . 1 $\frac{1}{3}$ . 20 . $\frac{7}{35}$ . 0,75
Bài 2 Tìm x biết
a) ( $\frac{3}{4}$ . x + 2$\frac{1}{2}$ ) . $\frac{-2}{3}$ = $\frac{1}{8}$
b) $\frac{1}{3}$ . x -0,5 . x = 0,75
Bài 1 Thực hiện phép tính
a) B = 50% . 1 $\frac{1}{3}$ . 20 . $\frac{7}{35}$ . 0,75
Bài 2 Tìm x biết
a) ( $\frac{3}{4}$ . x + 2$\frac{1}{2}$ ) . $\frac{-2}{3}$ = $\frac{1}{8}$
b) $\frac{1}{3}$ . x -0,5 . x = 0,75
Bài 1
a) `B=50% . 1 1/3 . 20 . 7/35 . 0,75`
`= 1/2 . 4/3 . 20 . 1/5 . 3/4`
`=2`
Bài 2
a) `(3/4 x + 2 1/2) . (-2/3) = 1/8`
`-> 3/4 x + 5/2 = 1/8 : (-2/3)`
`-> 3/4 x +5/2 = -3/16`
`->3/4 x = -3/16 -5/2`
`-> 3/4x=-43/16`
`-> x=-43/16 : 3/4`
`-> x=-43/12`
b) `1/3 .x -0,5 .x =0,75`
`-> (1/3 – 1/2) .x= 3/4`
`-> -1/6 x= 3/4`
`-> x=3/4 : (-1/6)`
`-> x=-9/2`.
Bài 1:
a) B = 50% . 1$\frac{1}{3}$ . 20 . $\frac{7}{35}$ . 0,75
B = $\frac{1}{2}$ . $\frac{4}{3}$ . 20 . $\frac{1}{5}$ . $\frac{3}{4}$
B = $\frac{2}{3}$ . 20 . $\frac{1}{5}$ . $\frac{3}{4}$
B = $\frac{40}{3}$ . $\frac{1}{5}$ . $\frac{3}{4}$
B = $\frac{8}{3}$ . $\frac{3}{4}$
B = 2
Bài 2:
a) ($\frac{3}{4}$ . x + 2$\frac{1}{2}$) . $\frac{-2}{3}$ = $\frac{1}{8}$
$\frac{3}{4}$ . x + 2$\frac{1}{2}$ = $\frac{1}{8}$ : $\frac{-2}{3}$
$\frac{3}{4}$ . x + $\frac{5}{2}$ = $\frac{-3}{16}$
$\frac{3}{4}$ . x = $\frac{-3}{16}$ – $\frac{5}{2}$
$\frac{3}{4}$ . x = $\frac{-43}{16}$
x = $\frac{-43}{16}$ : $\frac{3}{4}$
x = $\frac{-43}{12}$
Vậy x = $\frac{-43}{12}$
b) $\frac{1}{3}$ . x – 0,5 . x = 0,75
($\frac{1}{3}$ – 0,5) . x = $\frac{3}{4}$
($\frac{1}{3}$ – $\frac{1}{2}$) . x = $\frac{3}{4}$
$\frac{-1}{6}$ . x = $\frac{3}{4}$
x = $\frac{3}{4}$ : ($\frac{-1}{6}$)
x = $\frac{-9}{2}$
Vậy x = $\frac{-9}{2}$