We consider different cases based on the values of x: Case 1: x≥4. In this case, x−2>0, x−3>0, and x−4≥0, so ∣x−2∣=x−2, ∣x−3∣=x−3, and ∣x−4∣=x−4. Thus, the equation becomes
x−2+x−3+2(x−4)=9 x−2+x−3+2x−8=9 4x−13=9 x=422=211=5.5 Since 5.5≥4, x=5.5 is a valid solution. Case 2: 3≤x<4. In this case, x−2>0, x−3≥0, and x−4<0, so ∣x−2∣=x−2, ∣x−3∣=x−3, and ∣x−4∣=−(x−4)=4−x. Thus, the equation becomes
x−2+x−3+2(4−x)=9 x−2+x−3+8−2x=9 This is a contradiction, so there are no solutions in this case.
Case 3: 2≤x<3. In this case, x−2≥0, x−3<0, and x−4<0, so ∣x−2∣=x−2, ∣x−3∣=−(x−3)=3−x, and ∣x−4∣=−(x−4)=4−x. Thus, the equation becomes
x−2+3−x+2(4−x)=9 x−2+3−x+8−2x=9 However, 2≤x<3, so x=0 is not a valid solution. Case 4: x<2. In this case, x−2<0, x−3<0, and x−4<0, so ∣x−2∣=−(x−2)=2−x, ∣x−3∣=−(x−3)=3−x, and ∣x−4∣=−(x−4)=4−x. Thus, the equation becomes
2−x+3−x+2(4−x)=9 2−x+3−x+8−2x=9 13−4x=9 Since x<2, x=1 is a valid solution. Therefore, the solutions are x=1 and x=5.5.