Tách ra từng câu dc ko 

đa nhân đa đó bn 

\(\left(a+b\right)\left(a+b\right)\left(a+b\right)\\ =\left(a^2+ab+ab+b^2\right)\left(a+b\right)\\ =a^3+a^2b+ab^2+a^2b+ab^2+a^2b+ab^2+b^3\\ =a^3+3a^2b+3ab^2+b^3\)

a. \(\left(2x+1\right).2907=8721\\ 2x+1=8721:2907\\ 2x+1=3\\ 2x=2\\ x=1\)

b.\(\left(4x-16\right):1905=60\\ 4x-16=60.1905\\ 4x-16=114300\\ 4x=114300+16\\ 4x=114316\\ x=28579\)