$B1:$

$17,58×43+57×17,58$

$=17,58×(43+57)$

$=1758$

$43,57×2,6×(630-315×2)$

$=43,57×2,6×(630-630)$

$=43,57×2,6×0$

$=43,57×0$

$=0$

$45×16- 17/45 ×15+28$

$=(45×16)-(17/45×15)+28$

$=720-5+28$

$=715+28$

$=743$

$B2:$

x:2+ $\frac{3}{4}$ =$\frac{6}{7}$ 

x:2  =$\frac{6}{7}$ -$\frac{3}{4}$ 

x:2  =$\frac{3}{28}$ 

x     =$\frac{3}{28}$ ×2

x     =$\frac{3}{14}$ 

$33,3:(x-3,5)+45,7=799$

$33,3:(x-3,5)  =799-45,7$

$33,3:(x-3,5)  =753,3$

        $x-3,5   =33,3:753,3$

        $x-3,5   =37/837$

$(x-1)+(x-2)+(x-3)+(x-4)=30$

$x-1+x-2+x-3+x-4=30$

$4x + 10=30$

$4x=40$

$x=10$

17,58x43+57x17,58=17,58x(43+57)=17,58x100=1758

43,57x2,6x(630-315x2)=43,57x2,6x0=0

$\frac{45x16-17}{45x15+28}$=$\frac{703}{703}$ =1

Tìm x

X/2+3/4=6/7

<=>(14 x X)/28+(3x7)/28=(6x4)/28

<=>14 x X+21=24

<=>14 x X=3

<=>X=3/14

33,3:(X-3,5)+45,7=799

<=>33,3:(X-3,5)=799-45,7=753,3

<=>X-3,5=753,3/33,3=22,62

<=>X=26,12

(X-1)+(X-2)+(X-3)+(X-4)=30

<=>X-1+X-2+X-3+X-4=30

<=>4 x X + 10=30

<=>4 x X=40

<=>X=10