Question

Resolva a questão numero 1 letra a

Answer 1

(3x).(-1,4x²y).(-5y)
(-4,2x³y).(-5y)
21,0x³y²

Eu acho que resolve assim

Answer 2

a) (3x).(-1,4x²y).(-5y)=  21x³y²

b)-2a(x+4) = -2ax-8a 

c)(x+5).(x²+2x-10)=  x³+2x²-10x+5x²+10x-50= x³+7x²-50

d) (b-a)(2b-a)= 2b²- ba-2ab+a²= 2b²-3ab+a²

e) (5-x).(x²+1)= 5x²+5-x³-x=  -x³+5x²-x+5