Question

A= 5x⁵- 5x⁴ + 5X³ - 5x² + 5x -1 tại x 4 cíu nốt đi

Answer 1

x=4 nên x+1=5

\(A=x^5\left(x+1\right)-x^4\left(x+1\right)+x^3\left(x+1\right)-x^2\left(x+1\right)+x\left(x+1\right)-1\)

\(=x^6+x^5-x^5-x^4+x^4+x^3-x^3-x^2+x^2+x-1\)

\(=x^6-1=4^6-1=4095\)

Answer 2

Vì x = 4 nên x + 1 = 5
A = (x+1)x⁵ - x⁴(x+1) + x³(x+1) - x²(x+1) + x(x+1) - 1
= x⁶ + x⁵ - x⁵ - x⁴ + x⁴ + x³ - x³ - x² + x² + 1 - 1
= x⁶ + 1 - 1
Thay x = 4 vào A ta có:
A= 4⁶  + 1- 1
= 4096