Question

tìmh

 

Answer 1

a) l2x - 3l + 3 = 16

=> l2x + 3l = 16 - 3 =  13

=> 2x + 3 = 13 và 2x + 3 = -13

* 2x + 3 = 13

=> x = (13 - 3) : 2 =  5

* 2x + 3 = -13  

=> x = (-13 - 3) : 2 = -8

b) 42 + 3/7 x l3x - 1l = 12

 =>      3/7 x l3x - 1l = 12 - 42 = -30

=>        l3x - 1l = -30 : 3/7

=>      l3x - 1l =  -70

=>  x ko tồn tại

c)  l2x - 1l = lx + 2l

=>  2x - 1 = x + 2

=> -1 - 2 = x - 2x 

=>   -3    = -x

=>  x = 3

d) \(\frac{x+2}{5}=\frac{2-3x}{3}\) 

\(\Rightarrow3\left(x+2\right)=5\left(2-3x\right)\)

\(\Rightarrow3x+6=10-15x\)

\(\Rightarrow3x+15x=10-6\)

\(\Rightarrow x\left(3+15\right)=4\)

\(\Rightarrow18x=4\)

\(\Rightarrow x=\frac{4}{18}=\frac{2}{9}\)