第一題（8+12+10）*4=120
第二題-(a^2*b)*(2ab)^3+10*a^5*b^4
= -a^2 * b * 8 * a^3 * b^3 + 10 * a^5 * b^4
= -8 * a^5 * b^4 + 10 * a^5 * b^4
= 2 * a^5 * b^4
第三題(-2x^2)*(-y)+3xy*(1-1/3x)
= 2 * x^2 * y + 3xy - x^2 * y
= x^2 * y + 3xy
第四題當(dāng)n為奇數(shù)時(shí) x = [(-1) - (1)]/2 = -1
S = x+2x^2+3x^3+……+99x^99+100x^100
= -1 + 2 - 3 + ... - 99 + 100
= 1 + 1 + ... + 1 (50項(xiàng))
= 50
當(dāng)n為偶數(shù)時(shí) x = [1 - (-1)]/2 = 1
S = x+2x^2+3x^3+……+99x^99+100x^100
= 1 + 2 + 3 + ... + 99 + 100
= 100 * (1 + 100)/ 2
= 5050
第五題(2^3)^8*2^(-2)^12*(-1)^12
=2^(3*8)* 2^(-24)*1
=1