A/ X X2( 2 4)  X2  4 X4 4 X2 X2 4  ( X4 4 X2 4)  X2  (...

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a/ ^{x x}

⁽

^{ 4)  x}

^{  4 x}

^{ 4 x}

^{ x}

^{ 4}

^{ ( x}

^{ 4 x}

^{ 4)  x}

^{ ( x}

^{ 2)}

^{ x}

^{ ( x}

^{  2 x x )(}

^{  2 x )}

b/ ^x

^{ 2 xy y }

^{ 3 x  3 y  10 (  x y  )}

^{ 3( x y  ) 10 }

Đặt: t = x-y , ta có đa thức:t ² +3t-10 = ( t ² +5t)-(2t+10)= t(t+5)-2(t+5)=(t+5)(t-2) (*)

Thay t=x-y vào (*) ta được : (x-y+5)(x-y-2)

Vậy : x ² -2xy+y ² +3x-3y-10=(x-y+5)(x-y-2)

c/ a(b ² -c ² )-b(a ² -c ² )+c(a ² -b ² ) = ab ² -ac ² -a ² b+bc ² +a ² c-b ² c = (ab ² -b ² c)+(a ² c-ac ² )-(a ² b-bc ² )

=b ² (a-c)+ac(a-c)-b(a ² -c ² ) = (a-c)(b ² +ac-ab-bc) = (a-c)[(b ² -bc)-(ab-ac)]

=(a-c)[b(b-c)-a(b-c)] = (a-c)(b-c)(b-a)