Toán đại 8-bài rút gọn

T

toiyeu9a3

Nhân tung ra thôi bạn
a. Bt =$64x^3 + 48x^2 + 36x - 48x^2 -36x - 27 - 72x^3 - 120x^2 - 50x + 60x$
= $-8x^3 - 120x^2 + 10x - 27$
 
S

sentai2014

$(1-3a)^3-(3a-4)(5+3a)(5-3a)-(2+3a)(2-3a)$
$=1^3-9a+27a^2-27a^3-(3a-4)(5^2-3a^2)-(2^2-9a^2)$
$=1-9a+27a^2-27a^3-(75a-27a^3-100+36a^2)-(4-9a^2)$
$=1-9a+27a^2-27a^3-75a+27a^3+100-36a^2-4+9a^2$
$=1-9a+27a^2-75a+100-36a-4+9a^2=(1+100-4)+(27a^2-36a^2+9a^2)-9a-75a$
$=97-9a-75a=97-a(9+75)=97-84a $
 
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