(1) (4a-b²)*(-2b)=4a*(-2b)-b²*(-2b)=-8ab+2b³
(2) 2*x²(x-1/2)=2*x²*x-2*x²*1/2=2x³-x²
(3) 5ab*(2a-b+0.2)=5ab*2a-5ab*b+5ab*0.2=10a²b-5ab²+ab
(4)(2a²-2a/3-4/9)题目错了吧.
(1) (4a-b²)*(-2b)=4a*(-2b)-b²*(-2b)=-8ab+2b³
(2) 2*x²(x-1/2)=2*x²*x-2*x²*1/2=2x³-x²
(3) 5ab*(2a-b+0.2)=5ab*2a-5ab*b+5ab*0.2=10a²b-5ab²+ab
(4)(2a²-2a/3-4/9)题目错了吧.