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Linear Equations And Inequalities

Solution of inequalities

Math

Q# 1: Find the solution set of 3x+1<7 ,xW\forall x\in W and show on the number line.

Solution:

  • First understand the meaning of xW\forall x\in W \forall= For all values \in= belongs to W= whole numbers So it is basically saying the inequality is only for all values of x that belongs to whole numbers. So the solution set will have only whole numbers.

  • Now Write the Inequality

    3x+1<7

  • Solve the constant

    3x<7-1

    3x<6

  • Divide by the coefficient of the variable

    \frac{3x}{3} < \frac{6}{3}

    x<2

  • Our solution will only contains whole numbers and the answer is suggesting that all values less than 2. Therefore, the solution set is {0,1}\{0,1\} and represented in number line as:

Q# 2: Find the solution set of -6<2x+1<11, \forall x\in Z and show on the number line.

Solution:

  • First understand the meaning of xZ\forall x\in \Z \forall= For all values \in= belongs to Z= Integers So it is basically saying the inequality is only for all values of x that belongs to integers. So the solution set will have only integer numbers.

  • Now Write the Inequality

    -6<2x+1<11

  • Since there are two inequalities, it can be expressed as

    -6<2x+1 and 2x+1<11

  • Solve the constant

    -6-1<2x and 2x<11-1

    -7<2x and 2x<10

  • Divide by the coefficient of the variable

    \frac{-7}{2}<\frac{2x}{2} and \frac{2x}{2}<\frac{10}{2}

    \frac{-7}{2}<x and x<5

    -3.5<x and x<5

  • Our solution will only contains integer numbers and the answer is suggesting that all values greater than -3.5 and less than 5. Therefore, the solution set is {3,2,1,0,1,2,3,4}\{-3,-2,-1,0,1,2,3,4\} and represented in number line as: