a) $3x^{n}$ . ( 6$x^{m – 3}$ + 1 ) – $2x^{n}$ . ( $9x^{n – 3}$ – 1 )
b) $5^{n + 1}$ – 4 . $5^{n}$
c) $6^{2}$ . $6^{4}$ – $4^{3}$ . ( $3^{6}$ – 1 )
a) $3x^{n}$ . ( 6$x^{m – 3}$ + 1 ) – $2x^{n}$ . ( $9x^{n – 3}$ – 1 )
b) $5^{n + 1}$ – 4 . $5^{n}$
c) $6^{2}$ . $6^{4}$ – $4^{3}$ . ( $3^{6}$ – 1 )
Giải thích các bước giải:
a/ $3x^n.(6x^{n-3}+1)-2x^n.(9x^{n-3}-1)$
$=3x^n.6x^{n-3}+3x^n-2x^n.9x^{n-3}+2x^n$
$=18x^{2n-3}+5x^n-18x^{2n-3}$
$=5x^n$
b/ $5^{n+1}-4.5^n$
$=5^n.5-4.5^n$
$=5^n.(5-4)$
$=5^n$
c/ $6^2.6^4-4^3.(3^6-1)$
$=6^6-4^3.3^6+4^3$
$=(6^2)^3-4^3.(3^2)^3+4^3$
$=36^3-4^3.9^3+4^3$
$=36^3-36^3+4^3$
$=4^3$
$=64$
Chúc bạn học tốt !!!