Đáp án+Giải thích các bước giải:
$e) M=x²+1-(x-1)²+2x$
$=x²+1−(x−1)(x−1)+2x$
$=x²+1−(x²−x−x+1)+2x$
$=x²+1−x²+x+x-1+2x$
$=4x$
$f) N=x²+5-(x+4)(x-4)$
$=x²+5−(x²−4x+4x−16)$
$=x²+5−x²+4x-4x+16$
$=21$
$g) P=2x²-(x+5)(x-5)-(x+5)(x-5)+40$
$=2x²−(x²−5x+5x−25)-(x²−5x+5x−25)+40$
$=2x²-x²+5x-5x+25-x²+5x-5x+25+40$
$=90$
$h) Q=(2x-5)²+(2x+5)(2x-5)-8x²+1$
$=(2x-5)(2x-5)+(2x+5)(2x-5)-8x²+1$
$=4x²−10x−10x+25+4x²−10x+10x−25−8x²+1$
$=−20x+1$
Chúc bn hc tốt🥰
$\text{#LinhSad}$
