Question

How do you evaluate the expression $\dfrac{jk}{j+k}$ when $j=-2$ and $k=3$?

Answer 1

Hint: Here in this question we have given the values of variables and an expression involves these variables. So to evaluate the given expression we just substitute the given values in place of variables and simplify the obtained equation to get the desired answer.

Complete step by step solution:
We have been given the values $j=-2$ and $k=3$.
We have to evaluate the expression $\dfrac{jk}{j+k}$.
We know that an algebraic expression contains variables, constants and algebraic operators. A variable is a quantity whose value changes and constant has a fixed value. To solve an expression containing variables and constants we need to solve the operations like addition, subtraction, multiplication and division given in the expression.
To evaluate the expression we just substitute the given values in the given expression. Then we will get
$\Rightarrow \dfrac{\left( -2 \right)\times 3}{-2+3}$
Now, simplifying the above obtained equation we will get
$\begin{align}
  & \Rightarrow \dfrac{-6}{1} \\
 & \Rightarrow -6 \\
\end{align}$

Hence by substituting the given values and evaluating the expression $\dfrac{jk}{j+k}$ we get the value $-6$.

Note: The point to be noted is that when we multiplied a negative number with a positive number we get the negative number. When we multiply two negative numbers we get a positive resultant. As this is a simple question so avoid basic calculation mistakes. Also if there are more than two operators given in the expression always follow the BODMAS rule to solve the expression.