Question

[Phan thị lành]

Tìm x:

a) (x+1) + (x+2) +....+ (x+100) = 5750

b) Cho C = 2 + 2^2 + 2^3 + ...+ 2^100

Tìm x để 2^2x-1 - 2 = C

c) (x^2 + 4) chia hết cho (x+2)            (x thuộc N)

e) 2^3 .x + 5^2.x = 2 (5^2 + 2^3) - 33                 (x thuộc N)

f) (3x - 4)^10 - 3= 1021                    (x thuộc N)

g) (4x - 3)^4 = (4x - 3)^2

h) 2^x+2 . 3^x+1 . 5^x = 10800

Answer 1

[Nguyễn Ngọc Quý]

(x+1) + (x+2) + ... + (x+100) = 5750

(x+x+...+x) + (1+2+..+100) = 5750

100x + (101 x 100 : 2 ) = 5750

100x + 5050 = 5750

=> 100x = 5750 - 5050 

100 x = 700

=> x = 700 : 100

=> x = 7              

Answer 2

[Asuna Yuuki]

\(a.\left(x+1\right)+\left(x+2\right)+...+\left(x+100\right)=5750\)

\(\left(x+x+x+...+x\right)+\left(1+2+3+4+...+100\right)=5750\)

\(100x+\left(1+2+3+4+...+100\right)=5750\)

\(100x+5050=5750\)

\(100x=5750-5050\)

\(100x=700\)

\(x=700:100\)

\(x=7\)