Question

How do you evaluate the expression \[15a-2\left( b+c \right)\], for \[a=2\], \[b=3\] and $c=4$?

Answer 1

Hint: In this question we have been given with an algebraic expression which we have to evaluate for the given values of the variables. We have three variables in the algebraic expression which are $a,b$ and $c$. We will solve the expression by substituting the values of the given variables and simplify the expression to get the required solution.

Complete step-by-step solution:
We have the expression given to us as:
\[\Rightarrow 15a-2\left( b+c \right)\]
We can see that the algebraic expression consists of total $3$ variables in It which are $a,b$ and $c$.
We know the values of the variables as:
\[a=2\]
\[b=3\]
$c=4$
On substituting these values in the expression, we get:
\[\Rightarrow 15\left( 2 \right)-2\left( \left( 3 \right)+\left( 4 \right) \right)\]
On simplifying the bracket, we get:
\[\Rightarrow 15\left( 2 \right)-2\left( 7 \right)\]
On multiplying the values, we get:
$\Rightarrow 30-14$
On simplifying, we get:
$\Rightarrow 16$, which is the required solution.

Note: It is to be remembered that evaluating an algebraic expression means that we have to substitute the values of all the variables present and find its numerical value. If the value of even a single variable is changed, then the entire numerical value of the algebraic expression would change. It is also to be remembered that the variables can be in terms of exponents and logarithms too. The precedence rule $PEMDAS$ should be remembered while evaluating algebraic expression which means that the expression should be solved in the sequence of parenthesis, exponents, multiplication, division, addition and subtraction respectively. if the precedence rules are not followed, the value of the expression might vary.