What will come in place of the question mark (?) in the following question?

$\frac{?+5}{7}+\frac{9}{21}=\frac{36}{21}$

The correct answer is 4.

Let us solve the equation step-by-step to find the value that replaces the question mark (?). Let the question mark (?) be represented by the variable $x$.

The given equation is:

$\frac{x+5}{7}+\frac{9}{21}=\frac{36}{21}$

First, let us isolate the term containing $x$ on the left-hand side of the equation by subtracting $\frac{9}{21}$ from both sides:

$\frac{x+5}{7}=\frac{36}{21}-\frac{9}{21}$

Since the fractions on the right-hand side have the same denominator, we can subtract their numerators directly:

$\frac{x+5}{7}=\frac{36-9}{21}$

$\frac{x+5}{7}=\frac{27}{21}$

Next, we can simplify the fraction $\frac{27}{21}$ by dividing both the numerator and the denominator by their greatest common divisor, which is 3:

$\frac{27}{21}=\frac{27/3}{21/3}=\frac{9}{7}$

Now substitute this simplified fraction back into the equation:

$\frac{x+5}{7}=\frac{9}{7}$

Since the denominators on both sides of the equation are equal, their numerators must also be equal:

$x+5=9$

Subtract 5 from both sides to find the value of $x$:

$x=9-5$

$x=4$

Therefore, the value that comes in place of the question mark is 4.