Question

Solve the given equation
$3x+5=17$

• A. $x=3$
• B. $x=4$
• C. $x=5$
• D. This equation cannot be solved

Answer 1

The correct option is B

$x=4$

Solve an equation refers to finding the value of the unknown quantity in the equation
In the above equation, the variable, or the unknown quantity, is $x$
Now, to find the value of the unknown quantity x, we do the following
Given that $3x+5=17$
Now, all terms containing the unknown quantity, i.e., x, must be taken to one side, and all the known quantities must be taken to the other side
The convention followed is this. The left hand side of the equation will have the unknown quantity x
Thus, we shall shift 5 to the right hand side.
$3x=17-5$ Note that when +5 goes to the right hand side, it becomes -5.
Hence, $3x=12$
Now, the unknown quantity is multiplied by 3. Hence, we shift the 3 to the right hand side. In doing so, multiplication changes to division.
$x=\frac{12}{3}=4$