Question

[Con rồng hắc ám]

1, Tính :

a, A = 1.(-1)+3.(-1)^2+5.(-1)^3.7+(-1)^4+9.(-1)^5

b, 1-2-3+4+5-6-7+8+...+61-62-63-64

Answer 1

[Tú]

\(A=1.\left(-1\right)+3.\left(-1\right)^2+5.\left(-1\right)^3.7+\left(-1\right)^4+9.\left(-1\right)^5\)

\(A=1.\left(-1\right)+3.1+5.\left(-1\right).7+1+9.\left(-1\right)\)

\(A=\left(-1\right)+3+\left(-5\right).7+1+\left(-9\right)\)

\(A=-1+3-35+1-9\)

\(A=-41\)