Question

Evaluate the value of expression 5c – 3d + 11, when c = 7 and d = 8.

Answer 1

Hint: This is a type of linear equation. The value of the linear equation in two variables is evaluated by putting the values of the variables given in question.

Complete step-by-step answer:
We will start our solution by finding out what kind of term is given in the question. The term given in question is a linear function in two variables. A linear function in two variables is a function which contains two independent variables. The form of linear function of two variables is generally, $f\left( x,y \right)=ax+by+c$ , where a, b and c are constants. The value of this function at any point $\left( x,y \right)$ is given by putting these values in place of $x$ and $y$ . Now we proceed to the linear function given in our question. The function given is:
$f\left( c,d \right)=5c-3d+11$
Here, a, b and c are 5, -3 and 11 respectively. Now, according to the question, we have to find the value of this function when c will be equal to 7 and d will be equal to 8. So now we will put these values in the function $f\left( c,d \right)$ . Thus, after putting these values, we get
$\begin{align}
  & f\left( 7,8 \right)=5\left( 7 \right)-3\left( 8 \right)+11 \\
 & f\left( 7,8 \right)=35-24+11 \\
 & f\left( 7,8 \right)=22 \\
\end{align}$
So, after putting the values of c and d as 7 and 8 respectively in the equation, we get the final answer as $f\left( 7,8 \right)=22$ .

Note: In the above function, we have a linear function not a linear equation in two variables. So, we cannot equate the term given to zero because that is not what the question is asking.