(2a+3b) = 2*1/2+3*(-2/3) = 1-2 = -1 ;
所以
2(2a+3b)²-3(2a+3b)+8(2a+3b)²-(2a+3b)
= (2a+3b)[2(2a+3b)-3+8(2a+3b)-1]
= (2a+3b)[10(2a+3b)-4]
=(-1)*[-10-4]
=14
(2a+3b) = 2*1/2+3*(-2/3) = 1-2 = -1 ;
所以
2(2a+3b)²-3(2a+3b)+8(2a+3b)²-(2a+3b)
= (2a+3b)[2(2a+3b)-3+8(2a+3b)-1]
= (2a+3b)[10(2a+3b)-4]
=(-1)*[-10-4]
=14