2x ^2 – 2xy – 5x + 5y; b) 8x^2 + 4xy – 2ax – ay;
c) x^3 – 4x^2 + 4x; d) 2xy – x^2 – y^2 + 16;
e) x^2 – y^2 – 2yz – z^2; g) 3a^2 – 6ab + 3b^2 – 12c^2.
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2x ^2 – 2xy – 5x + 5y; b) 8x^2 + 4xy – 2ax – ay; c) x^3 – 4x^2 + 4x; d) 2xy – x^2 – y^2 + 16
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Khải Quang
Đáp án:
Giải thích các bước giải:
a) 2x2−2xy−5x+5y2×2−2xy−5x+5y
=y(5−2x)−x(5−2x)
=(5−2x)(y−x).
b) 8x2+4xy−2ax−ay
=2x(4x−a)+y(4x−a)
c) x3−4x2+4x
=x(x2−4x+4)
=x(x−2)2
d) 2xy−x2−y2+162xy−x2−y2+16
=(x2−2xy+y2−42)
e) x2−y2−2yz−z2
=x2−(y2+2yz+z2)
=x2−(y+z)2
=(x−y+z)(x+y+z)
g) 3a2−6ab+3b2−12c2
=3(a2−2ab+b2−4c2)
=3[(a−b)2−(2c)2]
=−(x2−2xy+y2−42)=−(x2−2xy+y2−42)
=−[(x−y)2−42]=−[(x−y)2−42]
=−(x−y−4)(x−y+4)
=x²-(y+z)²=(x-y-z)=(x+y+z)
bn học tốt nhá<3
Dulcie
Đáp án:
Giải thích các bước giải:
A) 2x^2 – 2xy – 5x + 5y
= ( 2x^2 – 2xy ) – ( 5x + 5y )
= 2y – xy
B) 8x^2 + 4xy -2ax -ay
= 64x + 4xy – 2ax – ay
= ( 64x + 4xy ) – ( 2ax + ay )
= 68x^2y – 2xy
= 68^2
C) x^ 3 – 4x^2 + 4x
= ( x^3 – 4x^2 ) + 4x
= 4x + 4x
= 16x^2
D) 2xy – x^2 – y^2 + 16;
= 2xy – x^2 – y^2 + 16
= 2xy – ( x^2 + y^2 ) +16
= 2xy – xy + 16
E ) x^2 – y^2 – 2yz – z^2
= x^2 – y^2 + 2yz + z^2
= ( x^2 – y^2 + z^2 ) + 2yz
= xyz + 2yz
G) 3a^2 – 6ab + 3b^2 – 12c^2.
= 3a^2 – 6ab – 3b^2 + 12c^2
= ( 3a^2 – 3b^2 + 12c^2 ) – 6ab
= 12abc – 6ab
= 6c