Question

Find all real numbers x such that |7x − 4| = 38

Answer 1

Hello,

if 7x-4>=0 (or x>=4/7) then
|7x-4|=7x-4
7x-4=38
==>7x=42
==>x=6

if 7x-4<0 (or x<4/7) then
|7x-4|=-7x+4

-7x+4=38
==>-7x=34
==>x=-34/7

sol={6; -34/7}