Question

How do you evaluate $5x+8$ for $x=3$ ?

Answer 1

Hint: To solve above question we need to mind the BODMAS rule and rewrite the equation $5x+8$ by replacing the $x$ with 3. We know the BODMAS rule says we need to solve the brackets first, then of, then divide, then multiplication, then addition and then subtraction. So in the given equation in the place of $x$ we will put $3$.

Complete step by step solution:
 Now write the above equation $5x+8$ by replacing $x$ with 3 then we get,
$\Rightarrow 5(3)+8$
Now put $x=3$ then,
Now we will solve the multiplication first we get,
$\Rightarrow 15+8$
Now we add them then we get,
$\Rightarrow 23$

Hence by using BODMAS rule we find the value of the given equation $5x+8$=23 with $x=3$

Note: To check whether the answer is right or wrong we should put the above equation $5x+8$ equals to answer $23$ and evaluate (find) the value of $x$.
So, by comparing the equation and answer we get,
$\Rightarrow 5(x)+8=23$
We transfer 8 on the other side as $-8$ or simply we can say subtract $8$ from both side we get,
$\Rightarrow 5(x)=23-8$
Now subtracting $8$ from $23$ we gets,
$\Rightarrow 5(x)=15$
Now transfer 5 on other side as $\dfrac{1}{5}$ or we can say divide by $5$ from both side we get,
$\Rightarrow x=\dfrac{15}{5}$
$\Rightarrow 3$
Since the obtained value of $x$ is equal to the given value of $x$ that $x=3$ it means our answer is fully correct. It's very easy to evaluate these types of functions only just by putting the value of $x$. We can go wrong by applying wrong addition, multiplication, subtraction or division; we should always remember these four common operations of mathematics. And always check your answer as solved above.