Question 29670
The graphs look like {{{ graph(300,300,-160,20, -10, 100, abs(10x+60), abs(x+90) ) }}}.


Homing in on the 2 solutions, we see that {{{ graph(300,300,-20,20, -10, 100, abs(10x+60), abs(x+90) ) }}} which show the solutions to be about x=4 and x=-14. Roughly.


So, algebraically:
10x+60 = x+90
9x = 30
x = 30/9
x = 3.333333


10x+60 = -(x+90)
10x+60 = -x-90
11x = -150
x = -150/11
x = -13.636363..


jon