A=\(413^2-413.26+13^2=413^2-2.413.13+13^2\)

=> A=\(\left(413-13\right)^2=400^2=160000\)

chuc ban hoc tot

a)  \(413.\left(413-26\right)+169=413^2-2.13.413+13^2=\left(413-13\right)^2=160000\)

b)  \(\left(625^2+3\right).\left(25^4-3\right)-5^{16}+10\)

\(=\left(5^8+3\right)\left(5^8-3\right)-5^{16}+10\)

\(=5^{16}-9-5^{16}+10=1\)

c)  \(\frac{41^2+39^2+8^2.39}{41^2-39^2}=\frac{\left(41+39\right)^2}{\left(41-39\right)\left(41+39\right)}=\frac{41+39}{41-39}=\frac{80}{2}=40\)

Lời giải:

a. $=128-78+100-128=(128-128)+100-78=0+100-78=22$

b. $=125-100+93-218= (125+93-218)-100=0-100=-100$

c. $=453+74-79-527$

$=(453+74-527)-79 =0-79=-79$
d.

$=-825+775+825=(825-825)+775=0+775=775$

e.

$=163-413-187+637 = (163+637)-(413+187) = 800-600=200$

Bài 1:

\(a,413\left(413-26\right)+169\)

\(=413^2-26.413+13^2\)

\(=413^2-2.413.13+13^2\)

\(=\left(413-13\right)^2\)

\(=400^2\)

\(=160000\)

\(b,x^2+2x+1\)

\(=x^2+2.x.1+1^2\)

\(=\left(x+1\right)^2\)

\(=\left(99+1\right)^2\)

\(=100^2=10000\)

a) 9x² - 36

= ( 3x)² - 6²

= ( 3x - 6)( 3x + 6)

b) ax - ay - bx + by

= a( x - y) - b( x - y)

= ( x - y)( a - b)

c) y³ - 4y² + 3y

= y³ - y² - 3y² + 3y

= y²( y - 1) - 3y( y - 1)

= ( y - 1)( y² - 3y)

= y( y - 3)( y - 1)

Bài2 :

a ) \(9x^2-36=\left(3x\right)^2-6^2=\left(3x-6\right)\left(3x+6\right)\)

b )\(ax-ay-bx+by=a\left(x-y\right)-b\left(x-y\right)=\left(x-y\right)\left(a-b\right)\)

c ) \(y^3-4y^2+3y=y^3-y^2-3y^2+3y=y^2\left(y-1\right)-3y\left(y-1\right)=\left(y-1\right)\left(y^2-3y\right)\)

a)

3. x 13 = 45 − 26 . − 2 5 3. x 13 = 9 13 3. x = 9 x = 3

b)

13 21 − 3 2 . 21 13 + x = 4 13 − 27 42 . 21 13 + x = 4 13 − 27 26 + x = 4 13 x = 4 13 − − 27 26 x = 35 26

\(\left(413-127+42\right)-\left(413+127-48\right)\)

\(=413-127+42-413-127+48\)

\(=\left(413-413\right)-\left(127+127\right)+\left(42+48\right)\)

\(=-254+90=-164\)

( 413 - 127 + 42 ) - ( 413 + 127 - 48 ) 

= 413 - 127 + 42 - 413 - 127 + 48 

= ( 413 - 413 ) + ( 127 - 127 ) + ( 42 - 48 ) 

=   0     +      0       +        ( -6 ) 

= -6 

( 413 - 127 + 42 ) - ( 413 + 127 - 48 )

= 413 -127 + 42 - 413 - 127 + 48 

= ( 413 - 413 ) - ( 127 - 127 ) + 42 

415 / 413 - 413 / 413 = \(1\frac{2}{413}\)- 1 = \(\frac{2}{413}\)

a) 217 x 11

= 217 x (10 +1)

= 217 x 10 + 217 x 1

= 2170 + 217 = 2387

217 x 9 = 217 x (10-1)

= 217 x 10 - 217 x 1

= 2170 - 217 = 1953

b) 413 x 21 = 413 x (20 + 1)

= 413 x 20 + 413 x 1 = 8673

413 x 19 = 413 x (20-1)

= 413 x 20 - 413 x 1 = 7847

c) 1234 x 31 = 1234 x (30 +1)

= 1234 x 30+ 1234 x 1

= 37020 + 1234 = 38254

875 x 29 = 875 x (30 -1)

= 875 x 30 - 875 x 1

= 26250 - 875 = 25375

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