Question

Tính M = 3a².(a²-5)+a.(-3a³+4a)+6a²

 

Answer 1

\(M=3a^2.\left(a^2-5\right)+a.\left(-3a^3+4a\right)+6a^2\)

\(=3a^3-5a^2-3a^4+4a^2+6a^2\)

\(=-3a^4+3a^3+5a^2\)

Answer 2

Lời giải:

$M=(3a^4-15a^2)+(-3a^4+4a^2)+6a^2$

$=3a^4-15a^2-3a^4+4a^2+6a^2$

$=(3a^4-3a^4)+(-15a^2+4a^2+6a^2)=-5a^2$