MCQ 11 Mark
If $x \in R$, the solution set of $6 \leq-3(2 x-4)<12$ is
- A$\{x: x \in R, 0\}$
- ✓$\{x: x \in R, 0 \leq x<1\}$
- C$\{0,1\}$
- Dnone of these
Answer
View full question & answer→Correct option: B.
$\{x: x \in R, 0 \leq x<1\}$
$
\begin{aligned}
& x \in R \\
& 6 \leq-3(2 x-4)<12 \\
& \Rightarrow 6 \leq-3(2 x-4) \\
& \Rightarrow 6 \leq-6 x+12 \\
& \Rightarrow 6 \leq 12-6 \\
& \Rightarrow 6 x \leq 6 \\
& \Rightarrow x \leq \frac{6}{6} \\
& \Rightarrow x \leq 1
\end{aligned}
$
and
$
\begin{aligned}
& -3(2 x-4)<12 \\
& \Rightarrow-6 x+12<12 \\
& \Rightarrow-6 x<12-12 \\
& \Rightarrow-6 x<0 \\
& \Rightarrow x<0
\end{aligned}
$
From (i) and (ii),
$
\therefore 0< x \leq 1
$
Solution set $=\{x: x \in R
\begin{aligned}
& x \in R \\
& 6 \leq-3(2 x-4)<12 \\
& \Rightarrow 6 \leq-3(2 x-4) \\
& \Rightarrow 6 \leq-6 x+12 \\
& \Rightarrow 6 \leq 12-6 \\
& \Rightarrow 6 x \leq 6 \\
& \Rightarrow x \leq \frac{6}{6} \\
& \Rightarrow x \leq 1
\end{aligned}
$
and
$
\begin{aligned}
& -3(2 x-4)<12 \\
& \Rightarrow-6 x+12<12 \\
& \Rightarrow-6 x<12-12 \\
& \Rightarrow-6 x<0 \\
& \Rightarrow x<0
\end{aligned}
$
From (i) and (ii),
$
\therefore 0< x \leq 1
$
Solution set $=\{x: x \in R