Question
Solve the inequality: $-3 \leq 4-\frac{7 x}{2} \leq 18$

Answer

Given inequality $-3 \leq 4-\frac{7 x}{2} \leq 18$
$\Rightarrow-3 \leq 4-\frac{7 x}{2} \leq 18$
$\Rightarrow-3-4 \leq 4-\frac{7 x}{2}-4 \leq 18-4$
$\Rightarrow-7 \leq-\frac{7 x}{2} \leq 14$
Multiplying the inequality by -2.
$\Rightarrow$ (-7) $\times$ (-2) $\geq-\frac{7 x}{2} \times(-2) \geq 14 \times$ (-2)
$\Rightarrow$ 14 $\ge$ 7x $\ge$ -28
$\Rightarrow$ -28 $\le$ 7x $\le$ 14
Dividing the inequality by 7
$\Rightarrow$ -4 $\le$ x $\le$ 2
$\therefore$ all real numbers x greater than or equal to -4 but less than or equal to 2 are the solution of given equality.
x $\in$ [-4, 2] solution set =[-4,2]

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