(2x-1)^5=C(5,0)(2x)^5+C(5,1)(2x)^4(-1)+C(5,2)(2x)^3(-1)^2+C(5,3)(2x)^2(-1)^3+C(5,4)(2x)^1(-1)^4+C(5,5)(-1)^5
=32x^5-60x^4+80x^3-40x^2+10x-1
(2x-1)^5=a5*x^5+a4*x^4+a3*x^3+a2*x^2+a1*x+a0
a1=10
a2=-40
a3=80
a4=-60
a5=32
a1+a2+a5=10-40+32=2