Cách 1: Hàng ngang

\(A+B=\left(5x^2y+3xy^2+2yz\right)+\left(-5xy^2+2x^2y-2yz+2\right)\)

\(A+B=5x^2y+3xy^2+2yz-5xy^2+2x^2y-2yz+2\)

\(A+B=\left(5x^2y+2x^2y\right)+\left(3xy^2-5xy^2\right)+\left(2yz-2yz\right)+2\)

\(A+B=7x^2y-2xy^2+2\)

Cách 2: Hàng dọc

\(\begin{matrix}_+A\left(x\right)=5x^2y+3xy^2+2yz\\B\left(x\right)=2x^2y-5xy^2-2yz+2\\\overline{A\left(x\right)+B\left(x\right)=7x^2y-2xy^2+2}\end{matrix}\)

Bạn viết dấu " \(=\) "  thẳng hằng với nhau nhá

198 x 27 + 198 x 72 + 198

= 198 x 27 + 198 x 72 + 198 x 1

= 198 x ( 27 + 72 + 1 )

= 198 x 100

= 19800

198 x(27+72+1)=198x100=19800

198 x 27 + 198 x 72 + 198 x 1

= 198 x ( 27 + 72 + 1)

= 198 x 100

= 19800

a) 36 x 25 x 4 = 36 x ( 25 x 4) = 36 x 100 = 3600

18 x 24 : 9= 24 x ( 18:9) = 24 x 2 = 48

41 x 2 x 8 x 5= 41 x 8 x ( 5x2) = 41 x 8 x 10 = 3280

b) 108 x (23 + 7)= 108 x 30 = 3240 

215 x 86 + 215 x 14 = 215 x ( 86 + 14) = 215 x 100 = 21500 

53 x 128 – 43 x 128= 128 x ( 53 - 43) = 128 x 10 = 1280

\(a,35\times25\times4=36\times100=3600\)

\(18\times24:9=18:9\times24=2\times24=48\)

\(41\times2\times8\times5=\left(2\times5\right)\times\left(41\times8\right)=10\times328=3280\)

\(b,108\times\left(23+7\right)=108\times30=3240\)

\(215\times86+215\times14=215\times\left(86+14\right)=215\times100=21500\)

\(53\times128-43\times128=128\times\left(53-43\right)=128\times10=1280\)

các bạn ơi nhớ mình là ai không các bạn hay trả lời câu hỏi của mình đó

\(\left(3x-2\right)^2-2\left(x-1\right)^2\)

\(=9x^2-18x+4-2\left(x^2-2x+1\right)\)

\(=9x^2-18x+4-2x^2+4x-2\)

\(=7x^2-14x+2\)

\(\left(3x-2\right)^2-2\left(x-1\right)^2=9x^2-12x+4-2x^2+4x-2=7x^2-8x+2\)

\(=9x^2-12x+4-2x^2+4x-2\\ =7x^2-8x+2\)

198 x 27 + 198 x 72 + 198

= 198 x (27 + 72 + 1)

= 198 x 100

= 19 800

#Phương

198 x 27 + 198 x 72 + 198

= 198 x 27 + 198 x 72 + 198 x 1

= 198 x ( 27 + 72 + 1 )

= 198 x 100

= 19800

Chúc bạn học tốt !!!

198 x 27 + 198 x 72 + 198

= 198 x 27 + 198 x 72 + 198 x 1

= 198 x ( 27 + 72 + 1)

= 198 x 100

= 19800

198 x 27 + 198 x 72 + 198

= 198 x 27 + 198 x 72 + 198 x 1

= 198 x ( 27 + 72 + 1 )

= 198 x 100

= 19800

k mình nhé !!!

198 x 27 + 198 x 72 + 198

= 198 x 27 + 198 x 72 + 198 x 1

= 198 x (27+72+1)

= 198 x 100 

=19800

198 x 27 + 198 x 72 + 198 x 1

= 198 x ( 27 + 72 + 1)

= 198 x 100

= 19800

\(\left(3x-2\right)^2-2\left(x-1\right)^2\)

\(=9x^2-12x+4-2\left(x^2-2x+1\right)\)

\(=9x^2-12x+4-2x^2+4x-2\)

\(=7x^2-16x+2\)

198 x 25 + 198 x 70 + 594 + 396

= 198 x 25 + 198 x 70 + 198 x 3 + 198 x 2

= 198 x (25 + 70 + 3 + 2)

= 198 x 100

= 19.800

Chúc bạn học tốt.

😁😁😁

Ta có:

\(198×25+198×70+594+396\)

\(=198×25+198×70+198×3+198×2\)

\(=198×\left(25+70+3+2\right)\)

\(=198×100\)

\(=19800\)

198 x 25 + 198 x 70 + 594 + 396

= 198 x 25 + 198 x 70 + 198 x 3 + 198 x 2

= 198 x (25 + 70 + 3 + 2)

= 198 x 100

= 19.800

Chúc bạn học tốt.

😁😁😁

a: (x+1)^3-x(x-2)^2+x-1=0

=>x^3+3x^2+3x+1-x(x^2-4x+4)+x-1=0

=>x^3+3x^2+4x-x^3+4x^2-4x=0

=>7x^2=0

=>x=0

b: =>x^3-3x^2+3x-1-x^3-27+3x^2-12=2

=>3x=2+1+27+12=39+3=42

=>x=14