Question

Tìm \(x\):

a) ( \(x\)+   1 ) + ( \(x\)+   4 ) + ( \(x\)+   7 ) + ( \(x\)+ 10 ) + .......+ ( \(x\)+   28 ) = 155

b) ( \(x\)x 0,25 + 1999 ) x 2000 = ( 53 + 1999 ) x 2000

c) 71+ 65 x 4 = \(x\)+   \(\frac{140}{x}\)+   260

AI LÀM NHANH , ĐẦY ĐỦ MK SẼ TICK NHÓE !!!!!

Answer 1

a) ( x + 1 ) + ( x + 4 ) + ( x + 7 ) + ( x + 10 ) + ... + ( x + 28 ) = 155

\(\Rightarrow\)( x + x + x + ... + x ) + ( 1 + 4 + 7 + 10 + ... + 28 ) = 155

\(\Rightarrow\)x10 + ( SSH: ( 28 - 1 ) : 3 + 1 = 10 ) = 155

\(\Rightarrow\)x10 + ( Tổng: ( 1 + 28 ) . 10 : 2 = 145 ) = 155

\(\Rightarrow\)x10 + 145 = 155

\(\Rightarrow\)x10 = 155 - 145 = 10

\(\Rightarrow\)x = 10 : 10 = 1

vậy x = 1

b) ( x . 0,25 + 1999 ) . 2000 = ( 53 + 1999 ) .2000

\(\Rightarrow\)500x + 3998000 = 106000 + 3998000

\(\Rightarrow\)500x + 3998000 = 4104000

\(\Rightarrow\)500x = 4104000 - 3998000 = 106000

\(\Rightarrow\)x = 106000 : 500 = 212

Answer 2

ái chà chà

Answer 3

Nhảm quá