Question

[Miki Thảo]

Tìm x.y \(\in\)

a) |x-5| - |-7| =|-12|

b) x.y +3y-2x=3

c) 2x.y+x-2y=5

Answer 1

[Nguyễn Ngọc Quý]

a) l x - 5l - l-7l = l-12l

lx - 5l - 7 = 12

lx-5 l = 12 + 7 =19

th1: x - 5 = 19

x = 19 + 5 = 24

th2: x - 5 = -19

x = -19 + 5

x = -14