Algebra · real student question

Solve the inequality 2x + 1 > x + 6.

Question

Solve

2x+1>x+62x+1>x+6

Step-by-step solution

  1. Collect the variable terms. Subtract xx from both sides — a safe operation that never changes an inequality's direction:

    2xx+1>6x+1>62x-x+1>6\qquad\Longrightarrow\qquad x+1>6

  2. Isolate xx. Subtract 11 from both sides:

    x>5x>5

    No division was needed at all, so there was never any risk of a sign flip.

  3. State the solution set. In interval notation (5,)(5,\infty), with 55 excluded because the original inequality is strict (>>, not \ge).

  4. Check the boundary and one point each side. At x=5x=5: left 1111, right 1111 — equal, so the strict inequality fails and the endpoint is correctly open. At x=6x=6: left 1313, right 1212, and 13>1213>12 ✓. At x=4x=4: left 99, right 1010 ✗. The raw inequality and x>5x>5 agree at 100100 exact rational points ✓.

  5. Compare with the sibling problem. The same inequality with x+7x+7 on the right gives x>6x>6: increasing the constant on the larger side pushes the crossing point right by exactly the same amount. In general 2x+1>x+c2x+1>x+c solves to x>c1x>c-1.

Answer

x>5x>5

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