
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.


1/ phân tích thành nhân tử ;
= C2-( a +b )2=( c-a -b ) . ( c+a +b )

\(25-a^2+2ab-b^2\)
\(=25-\left(a^2-2ab+b^2\right)\)
\(=5^2-\left(a-b\right)^2\)
\(=\left(5-a+b\right)\left(5+a-b\right)\)

\(36\left(a-b\right)^2-25\left(2a-1\right)^2=\left[6\left(a-b\right)\right]^2-\left[5\left(2a-1\right)\right]^2\)
\(=\left(6a-6b\right)^2-\left(10a-5\right)^2=\left(6a-6b-10a+5\right)\left(6a-6b+10a-5\right)\)
\(=\left(-4a-6b+5\right)\left(16a-6b-5\right)\)

\(x^2-y^2+4x+4\)
\(=\left(x+2\right)^2-y^2\)
\(=\left(x+2+y\right)\left(x+2-y\right)\)
\(4x^2-y^2+8\left(y-2\right)\)
\(=4x^2-\left(y^2-8y+16\right)\)
\(=4x^2-\left(y-4\right)^2\)
\(=\left(2x+y-4\right)\left(2x-y+4\right)\)

Ta có :
\(36\left(a-b\right)^2-25\left(2a-1\right)^2\)
\(=\left[6\left(a-b\right)\right]^2-\left[5\left(2a-1\right)\right]^2\)
\(=\left[6\left(a-b\right)+5\left(2a-1\right)\right]\left[6\left(a-b\right)-5\left(2a-1\right)\right]\)
\(=\left(6a+6b+10a-5\right)\left(6a+6b-10a+5\right)\)
\(=\left(16a+6b-5\right)\left(6b-4a+5\right)\)

\(100x^2-\left(x^2+25\right)^2=\left(10x\right)^2-\left(x^2+25\right)^2=\left(10x-x^2-25\right)\left(x^2+10x+25\right)\)
\(=-\left(x-5\right)^2\left(x+5\right)^2\)
\(b,x-y+5=a\text{ thì biểu thức bằng:}a^2-2a+4>0\text{ nên k phân tích đc}\)
\(d,x^3+27y^3=\left(x+3y\right)\left(x^2-3xy+9y^2\right)\)
a) 100x2 - ( x2 + 25 )2
= ( 10x )2 - ( x2 + 25 )2
= [ 10x - ( x2 + 25 ) ][ 10x + ( x2 + 25 ) ]
= ( -x2 + 10x - 25 )( x2 + 10x + 25 )
= -( x2 - 10x + 25 )( x2 + 10x + 25 )
= -( x - 5 )2( x + 5 )2
b) ( x - y + 5 )2 + 4 - 4( x - y + 5 ) ( 4 may ra còn phân tích được :)) )
= ( x - y + 5 )2 - 2( x - y + 5 ).2 + 22
= ( x - y + 5 - 2 )2
= ( x - y + 3 )2
c) a2 - 25( b - c ) ( không phân tích được :)) )
d) x3 + 27y3 = x3 + ( 3y )3 = ( x + 3y )( x2 - 3xy + 9y2 )

a) xy + y2 - x - y
= ( xy – x ) + ( y^2 – y )
= x (y – 1) + y (y – 1)
= (y – 1) (x + y)
b) 25 – x^2 + 4xy - 4y^2
= 5^2 – (x^2 – 4xy + 4y^2)
= 5^2 – (x – 2y)^2
= (5 – x + 2y)(5 + x – 2y)
Tik mình với
a2 - 25( b - c )2
= a2 - 52( b - c )2
= a2 - [ 5( b - c ) ]2
= a2 - ( 5b - 5c )2
= [ a - ( 5b - 5c ) ][ a + ( 5b - 5c ) ]
= ( a - 5b + 5c )( a + 5b - 5c )
\(a^2-25\left(b-c\right)^2\)
\(=a^2-\left[5\left(b-c\right)\right]^2\)
\(=a^2-\left(5b-5c\right)^2\)
\(=\left(a-5b+5c\right)\left(a+5b-5c\right)\)