Question 312586
3 + -4x _<3x - 18
-4x-3x<=-18-3
-7x<=-21
x>=-21/-7 Note the sign change due to dividing by a negative value.
x>=3 ans.
Proof:
Let x=3.1
3-4*3.1<=3*3.1-18
3-12.3<=9.3-18
-9<=-8.7