6*(x-5)-2*(4x+2) ≥ 80, in the numeric set Z (sorry if not right), the result i got was x ≥ -57, it should be write {-57,-58,-59,...} or {...,-59, -58, -57}? And why?
Actually, the solution is
x ≤ - 57
You can write your solution as
( - ∞ , -57 ]
The bracket shows that the number to its left is included in the solution...infinities are never bracketed but are shown with a parentheses beside them
6*(x-5)-2*(4x+2) ≥ 80 simplify
6x - 30 - 8x - 4 ≥ 80 combine like terms on the left
-2x - 34 ≥ 80 add 34 to both sides
-2x ≥ 114
divide both sides by -2......don't forget to reverse the inequality sign as we do in an inequality when we divide or multiply by a negative !!!
x ≤ - 57