12784

1453

5700

179

10158

  2x17x12+4x6x21+8x3x64

=(2x12)x17+(4x6)x21+(8x3)x64

=24x17+24x21+24x64

=24x(17+21+64)

=24x102

=2448

=2448

=2448

k mih nha

\(2\cdot17\cdot12+4\cdot6\cdot21+8\cdot3\cdot62\)

\(=\left(2\cdot12\right)\cdot17+\left(4\cdot6\right)\cdot21+\left(8\cdot3\right)\cdot62\)

\(=24\cdot17+24\cdot21+24\cdot62\)

\(=24\cdot\left(17+21+62\right)\)

\(=24\cdot100\)

\(=2400\)

\(-37\times86+37\times76\)

\(=37\times\left(-86+76\right)\)

\(=37\times\left(-10\right)\)

\(=-370\)

2.17.12+9.6.21+8.3.62=3030

đáp số:3030 nhá

ai k mk mk sẽ k lại cho ^^

2x17x12+9x6x21+8x3x62=3030

Đặt tổng trên là A

\(A=\left[\left(-37\right).86\right]+\left(37.76\right)\)

Áp dụng qui tắc dấu ngoặc, ta có:

\(A=\left[\left(-37\right)+37\right].\left(86+76\right)\)

\(A=0.\left(86+76\right)\)

\(A=0.162\)

\(A=0\)

Vậy A = 0

\(-37\times86+37\times76\)

\(=37\times\left(-86+76\right)\)

\(=37\times\left(-10\right)\)

\(=-370\)

=  225.55 +  225.55

=  451.1 

a)\(65.3,47+3,47.65\)
\(=65.\left(3,47+3,47\right)\)
\(=65.6,94\)
\(=451,1\)

\(65\times\left(3,47+3,47\right)=65\times6,94=451,1\)

a: \(78\cdot82=80^2-4=6400-4=6396\)

b: \(45^2+90\cdot55+55^2=100^2=10000\)

`30 xx 25 xx 7 xx8`

`=(30 xx7) xx (25xx8)`

`=210 xx200`

`=42000`

`----`

`75 xx 8 xx 12 xx 14`

`=(75xx8) xx(12xx14)`

`=600xx168`

`=100800`

\(a.30\times25\times7\times8=\left(30\times7\right)\times\left(25\times8\right)=210\times200=42000\)

\(b.75\times8\times12\times14=\left(75\times12\right)\times\left(8\times14\right)=900\times112=100800\)

\(a,30.25.7.8\\ =\left(30.7\right).\left(25.8\right)\\ =210.200\\ =42000\\ b,75.8.12.14\\ =\left(75.12\right).\left(8.14\right)\\ =900.112\\ =100800\)