Question

How do you solve the inequality $5 - 2x > 27$?

Answer 1

Hint: In this question we are asked to solve the inequality, and these types of questions can be solved taking all constant terms to one side and all terms containing $x$ to the other sides and then simplify the equation till we get the required result.

Complete step by step solution:
Inequalities are mathematical expressions involving the symbols >, <, $ \geqslant $ , $ \leqslant $ To solve an inequality means to find a range, or ranges, of values that an unknown x can take and still satisfy the inequality.
A linear inequality is an inequality in one variable that can be written in one of the following forms where\[a\]and\[b\]are real numbers and $a \ne 0$,
\[ax + b < 0;ax + b > 0;ax + b \geqslant 0;ax + b \leqslant 0\].
Now the give inequality is $5 - 2x > 27$,
This is inequality in form $ax + b > 0$, where \[a\] and \[b\] are constants,
Now taking the constant term to the other side we get,
\[ \Rightarrow ax > - b\],
Now taking all constant terms to one side we get,
\[ \Rightarrow x > - \dfrac{b}{a}\],
If a is positive the sign doesn’t change, and as equal to sign is there in the inequality one bracket will be closed bracket ,so solution for the above will be written as , ,
Now if a is negative then the sign changes, the equation becomes,
$ \Rightarrow x < \dfrac{{ - b}}{a}$,
As equal to sign is there in the inequality one bracket will be closed bracket ,so solution for the above will be written as $x \in \left( { - \infty ,\dfrac{{ - b}}{a}} \right)$,
Given inequality is $5 - 2x > 27$,
Subtract 5 to both sides of the inequality, we get,
$ \Rightarrow 5 - 2x - 5 > 27 - 5$,
Now simplify the equation we get,
$ \Rightarrow - 2x > 22$,
Now multiplying both sides with 2, we get,
$ \Rightarrow \dfrac{{ - 2x}}{2} > \dfrac{{22}}{2}$,
Now simplifying we get,
$ \Rightarrow - x > 11$,
Now multiply both sides with negative sign we get,
$ \Rightarrow - \left( { - x} \right) < - 11$,
And when we apply negative sign for a greater than sign then it becomes less than and when we apply negative sign for a less than sign then it becomes greater than
Now simplifying we get,
$ \Rightarrow \left( { - x} \right) > - 11$,
This can also be written as $\left( { - \infty , - 11} \right)$.

The solution of the given inequality $5 - 2x > 27$ is $\left( { - \infty , - 11} \right)$.

Note:
There are three ways to represent solutions to inequalities: an interval, a graph, and an inequality. Because there is usually more than one solution to an inequality, when you check your answer you should check the end point and one other value to check the direction of the inequality. When we work with inequalities, we can usually treat them similarly to but not exactly as we treat equalities.