Algebra · real student question

Solve the inequality 7x + 11 > 3(x + 1).

Question

Solve

7x+11>3(x+1)7x+11>3(x+1)

Step-by-step solution

  1. Expand the bracket on the right. Multiply the 33 by both terms inside:

    3(x+1)=3x+37x+11>3x+33(x+1)=3x+3\quad\Longrightarrow\quad 7x+11>3x+3

    Distributing before rearranging keeps the bookkeeping simple; trying to divide by 33 first would put a fraction on the left.

  2. Collect the variable terms on the side with the larger coefficient. Subtract 3x3x from both sides so the xx coefficient stays positive:

    4x+11>34x+11>3

  3. Move the constant across. Subtract 1111:

    4x>84x>-8

  4. Divide by 44. Since 4>04>0, the direction of the inequality is unchanged:

    x>2x>-2

  5. Verify with test values. At x=0x=0: left =11=11, right =3=3, and 11>311>3 \checkmark. At x=3x=-3: left =10=-10, right =6=-6, and 10>6-10>-6 is false \checkmark. At the boundary x=2x=-2 both sides equal 3-3, so the endpoint is correctly excluded by the strict inequality.

Answer

x>2,i.e. (2,)x>-2,\qquad\text{i.e. }(-2,\infty)

Need to solve a different problem like this? Open the solver →