Question

Giúp mình bài này vs Mình đang cần gấp Em cảm ơn rất nhiều

Answer 1

$A=(x+3)(x+7)-(x+5)(x-1)$

$=(x^2+10x+21)-(x^2+4x-5)=x^2+10x+21-x^2-4x+5$

$=6x+26$

$B=(x+8)^2-2(x+8)(x-2)+(x-2)^2$

$=[(x+8)-(x-2)]^2=10^2=100$

$C=x(x+4)(x-4)-(x^2+1)(x^2-1)$

$=x(x^2-4^2)-(x^4-1)=x^3-16x^2-x^4+1$

 

Answer 2

$D=(x-1)^3-(x+2)(x^2-2x+4)+3(x+4)(x-4)$

$=(x^3-3x^2+3x-1)-(x^3+2^3)+3(x^2-4^2)$

$=x^3-3x^2+3x-1-x^3-8+3x^2-48$

$=3x-49$
$E=(x^2+2)(x-3)-(x-3)(x^2+3x+9)-2(1-x)+3

$=x^3-3x^2+2x-6-(x^3-3^3)-2+2x+3$
$=x^3-3x^2+2x-6-x^3+27-2+2x+3$

$=(x^3-x^3)-3x^2+(2x+2x)+(-6+27-2+3)$
$=-3x^2+4x+22$

Answer 3

$F=(x+7)(x-7)-(x-7)^2-7(2x-1)$

$=(x-7)[(x+7)-(x-7)]-(14x-7)=14(x-7)-14x+7$

$=14x-98-14x+7=-91$
$G=3x(x-1)^2-2x(x+3)(x-3)+4x(x-4)$

$=3x(x^2-2x+1)-2x(x^2-9)+(4x^2-16x)$

$=3x^3-6x^2+3x-3x^3+18x+4x^2-16x$

$=(3x^3-3x^3)+(-6x^2+4x^2)+(3x+18x-16x)$

$=-2x^2+5x$