Question

What value of $x$ is the solution to this equation?
$4x-5=13$

• A. $x=5$
• B. $x=\frac{7}{2}$
• C. $x=\frac{9}{2}$
• D. $x=9$

Answer 1

The correct option is C $x=\frac{9}{2}$

Equation $4x-5=13$
Check which of $x=9,x=\frac{9}{2},x=\frac{7}{2}$, and $x=5$ is the solution of the equation. We will put the values of y one by one and check if the LHS is equal to RHS.

For $x=9$
LHS $=4\times 9-5=31$
RHS $=13$
LHS $\ne$ RHS
$x=9$ is not the solution of this equation.

For $x=\frac{9}{2}$

LHS $=4\times \frac{9}{2}-5=\frac{36}{2}-5$

$=18-5=13$

RHS $=13$
LHS $=$ RHS
$x=\frac{9}{2}$ is the solution of this equation.

For $x=\frac{7}{2}$

LHS $=4\times \frac{7}{2}-5=\frac{28}{2}-5$


$=14-5=9$

RHS $=13$

LHS $\ne$ RHS
$x=\frac{7}{2}$ is not the solution of this equation.

For $x=5$
LHS $=4\times 5-5=15$
RHS $=13$
LHS $\ne$ RHS
$x=5$ is not the solution of this equation.

Option B is correct.