How do you solve abs(x - 7)<10?

1 Answer
Apr 1, 2015

Absolute value equations or inequalities must be split in two.

For x>=7, (x-7) is positive, so the inequality is

x-7<10->x<17 (in total this means 7<=x<17)

For x<=7, (x-7) is negative, but the absolute turns it around:

7-x<10->x> -3 (this means -3 < x <=7)

Our total "solution space" is thus: -3 < x<17
graph{|x-7| [-16.38, 24.15, -4.57, 15.7]}