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a) (25x5 – 5x4 + 10x2) : 5x2 = (25x5 : 5x2 ) - (5x4 : 5x2 ) + (10x2 : 5x2 )
= 5x3 – x2 + 2
b) (15x3y2 – 6x2y – 3x2y2) : 6x2y
= (15x3y2 : 6x2y) + (– 6x2y : 6x2y) + (– 3x2y2 : 6x2y)
= \(\dfrac{15}{6}\)xy - 1 - \(\dfrac{3}{6}\)y = \(\dfrac{5}{2}\)xy - \(\dfrac{1}{2}\)y - 1.
đề dài nên T giải câu a thôi bn tự làm tiếp mấy câu khác nhé
2x^2 - 2y^2 - 6x - 6y
= 2(x^2-y^2) - 6(x+ y)
= 2(x-y)(x+y) - 6(x+y)
= (2(x-y)-6) (x+y)
a/ (x-1)2-(4x+3)(2-x)=x2-2x+1-(8x-4x2+6-3x)
=x2-2x+1-8x+4x2-6+3x=5x2-7x-6
b/ (15x3y2 - 6x2y3) : 3x2y2 = 5x - 2y
c/ \(\dfrac{x+7}{x-7}-\dfrac{x-7}{x+7}+\dfrac{4x^2}{x^2-49}\)=\(\dfrac{\left(x+7\right)^2-\left(x-7\right)^2+4x^2}{\left(x-7\right)\left(x+7\right)}\)=\(\dfrac{x^2+14x+49-\left(x^2-14x+49\right)+4x^2}{\left(x-7\right)\left(x+7\right)}\)=\(\dfrac{28x+4x^2}{\left(x-7\right)\left(x+7\right)}\)=\(\dfrac{4x\left(x+7\right)}{\left(x-7\right)\left(x+7\right)}\)=\(\dfrac{4x}{x-7}\)
d)5.(x-y)-y(x-y)
=(x-y)(5-y)
e) y.(x-z)+7(z-x)
=y.(x-z)-7(x-z)
=(x-z)(y-7)
a) (x + 3y) (2x2y - 6xy2)
= (x + 3y) + 2xy (x - 3y)
= 2xy [(x + 3y) (x - 3y)]
= 2xy (x2 - 3y2)
b) (6x5y2 - 9x4y3 + 15x3y4) : 3x3y2
= (6x5y2 : 3x3y2) + (-9x4y3 : 3x3y2) + (15x3y4 : 3x3y2)
= [(6 : 3) (x5 : x3) (y2 : y2)] + [(-9 : 3) (x4 : x3) (y3 : y2)] + [(15 : 3) (x3 : x3) (y4 : y2)]
= 2x2 + (-3xy) + 5y2
= 2x2 - 3xy + 5y2
a) (25x^5 – 5x^4 + 10x^2) : 5x^2
= (25x^5 : 5x^2) – (5x^4 : 5x^2) + (10x^2 : 5x^2)
= 5x^3 – x^2 + 2
b) (15x^3y^2- 6x^2y – 3x^2y^2) : 6x^2y
= (15x^3y^2 : 6x^2y) + (-6x^2y : 6x^2y) + (- 3x^2y^2 : 6x^2y)
=\(\frac{15}{6}xy-1-\frac{3}{6}y\)
=\(\frac{5}{2}xy-1-\frac{1}{2}y\)