Question

[Nguyen Thi Minh Hanh]

Tìm x:

a. ( x + 2 ) + ( x + 5 ) + ( x + 8 ) + ( x + 11 ) + ( x + 14 ) = 75

b. ( x + 1 ) + ( x + 3 ) + ( x + 5 ) + ... + ( x + 101 ) = 5400

Answer 1

[Yuan Bing Yan _ Viên Băng Nghiên]

a.(x+2)+(x+5)+(x+8)+(x+11)+(x+14)=75

=>(x+x+x+x+x)+(2+5+8+11+14)=75

=>Xx5+40=75

=>Xx5=75-40

=>Xx5=35

=>x=35:5

=>x=7