=1358 x (15+85)+358x(590-490)

=1358x100+358x100

=100x(1358+358)

=100x1716

=171600

= 1358 x ( 15 + 85) + 358 x ( 590 - 490)

= 1358 x 100 + 358 x 100

= 100 x ( 1358 + 358 ) 

= 100 x 1716 = 171600

a) 15 x 1358 + 590 x 358 + 85 x 1358 - 490 x 358 

=15 x 1358 +   85 x 1358 + 590 x 358 - 490 x 358 

=1358x(15+85)+358x(590-490)

=1358x100+358x100

=135800+35800

=171600

b) 9,3 x 45 + 9,3 x 5,7 - 18,6 

=9,3x(45+5,7)-18,6

=9,3x50,7-18,6

=471,51-18,6

=452,91

15x1358+590x358+85x1358-490x358

=(15x1358+85x1358) + (590x358-490x358)

=1358x(15+85) + 358x(590-490)

=1358x100+358x100

=135800+35800

=171600

a)\(x+678=7818\)
\(x=7818-678=7140\)
b)\(4029+x=7684\)
\(x=7684-4029=3655\)
c)\(x-1358=4768\)
\(x=4768+1358=6126\)

\(a,x+678=7818\)

\(x=7818-678\)

\(x=7140\)

\(b,4029+x=7684\)

\(x=7684-4029\)

\(x=3655\)

\(c,x-1358=4768\)

\(x=4768+1358\)

\(x=6126\)

96 x 6 +  1456 = 576 + 1456

                        = 2032

=576+1456

=2032

x =  2666

1456+x:6=678+9

1456+x:6=687

(1456+x):6=687

1456+x=687x6

1456+x=4122

x=4122-1456

x=2666

nhớ k nhé

-1456-(137-1456)-63

=-1456-137+1456-63

=0-137-63

=-137-63

=-200

200 nhé bn

b x 5 + b x 2 = 1456

b x ( 5 + 2 ) = 1456

b x 7 = 1456

b = 1456 : 7 

b =      208

bx5+bx2=1456

=> bx(5+2)=1456

=> bx7=1456

=> b   = 1456 :7

=> b   = 208

3107                            83857                       13002                           32089