Đáp án+Giải thích các bước giải:
$C=3x²(x²+2)+4x(x²-1)+(x²+2x+3)(3x²-2x+1)$
$=3x^4+6x²+4x³−4x+3x^4−2x³+x²+6x³−4x²+2x+9x²−6x+3$
$=6x^4+8x³+12x²−8x+3$
Bài 3: Tìm x, biết:
$b) 2x³(2x-3)-x²(4x²-6x+2)=0$
$⇔4x^4−6x³−(4x^4−6x³+2x²)=0$
$⇔4x^4−6x³−4x^4+6x³−2x²=0$
$⇔−2x²=0$
$⇔x=0$
$d) x(x-5)(x+5)-(x+2)(x²-2x+4)=17$
$⇔x²(x+5)−5x(x+5)−(x+2)(x²−2x+4)=17$
$⇔x³+5x²−5x²−25x−(x+2)(x²−2x+4)=17$
$⇔x³−25x−(x+2)(x²−2x+4)=17$
$⇔x³−25x−(x³−2x²+4x+2x²−4x+8)=17$
$⇔x³−25x−(x³+8)=17$
$⇔x³−25x−x³-8=17$
$⇔-25x-8=17$
$⇔-25x=25$
$⇔x=-1$
Chúc bn hc tốt🥰
$\text{#LinhSad}$
