TÌM X
a, x : $\frac{3}{4}$ + $\frac{1}{4}$ = $\frac{2}{3}$
b, $\frac{3}{4}$ . x + $\frac{1}{5}$ = $\frac{1}{3}$
c,16 [( $\frac{3}{5}$ . x + 8 ) : 21 + 9 ] = $\frac{7}{10}$
TÌM X
a, x : $\frac{3}{4}$ + $\frac{1}{4}$ = $\frac{2}{3}$
b, $\frac{3}{4}$ . x + $\frac{1}{5}$ = $\frac{1}{3}$
c,16 [( $\frac{3}{5}$ . x + 8 ) : 21 + 9 ] = $\frac{7}{10}$
a, x : $\frac{3}{4}$ + $\frac{1}{4}$ = $\frac{2}{3}$
x : $\frac{3}{4}$ = $\frac{2}{3}$ – $\frac{1}{4}$
x : $\frac{3}{4}$ = $\frac{5}{12}$
x = $\frac{5}{12}$ . $\frac{3}{4}$
x = $\frac{5}{16}$
b, $\frac{3}{4}$ . x + $\frac{1}{5}$ = $\frac{1}{3}$
$\frac{3}{4}$ . x = $\frac{1}{3}$ – $\frac{1}{5}$
$\frac{3}{4}$ . x = $\frac{2}{15}$
x = $\frac{2}{15}$ : $\frac{3}{4}$
x = $\frac{8}{45}$
c, 16[($\frac{3}{5}$ . x + 8):21 + 9] = $\frac{7}{10}$
($\frac{3}{5}$ . x + 8):21 + 9 = $\frac{7}{10}$ : 16
($\frac{3}{5}$ . x + 8):21 + 9 = $\frac{7}{160}$
($\frac{3}{5}$ . x + 8):21 = $\frac{7}{160}$ – 9
($\frac{3}{5}$ . x + 8):21 = $\frac{-1433}{160}$
$\frac{3}{5}$ . x + 8 = $\frac{-1433}{160}$ x 21
$\frac{3}{5}$ . x + 8 = $\frac{-30093}{160}$
$\frac{3}{5}$ . x = $\frac{-30093}{160}$ – 8
$\frac{3}{5}$ . x = $\frac{-31373}{160}$
=> x = $\frac{-31373}{96}$
Đáp án:
a)x:3/4+1/4=2/3
=>x:3/4 =5/12
=> x =5/16
Vậy x=5/16
b)3/4.x+1/5=1/3
=>3/4.x =2/15
=>x =8/45
Vậy x=8/45
c)16[(3/5.x+8):21+9]=7/10
=>(3/5.x+8):21+9 =7/160
=>(3/5.x+8):21 =-1433/160
=> 3/5.x+8 =-30093/160
=>3/5.x =-31373/160
=> x =-31373/96
Vậy x=-31373/96
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