Question

Tìm x thuộc Q biết rằng: 

a)   11/12 - (2/5 + x) = 2/3

b)   2.x (x - 1/7) = 0

c)   3/4 + 1/4 : x = 2/5

Answer 1

a) 11/12-(2/5+x)=2/3

=>2/5+x=11/12-2/3

=>2/5+x=1/4

=>x=1/4-2/5

=>x=-3/20

Answer 2

b) 2.x(x-1,7)=0

=>x(x-1,7)=0

=>x= 0 hoặc x-1,7=0

=>x=0 hoặc x= 1,7

Answer 3

3/4+1/4:x=2/5

=>1/4:x=2/5-3/4

=>1/4:x=-7/20

=>x=1/4:-7/20

=>x=-5/7