Question

If $p=-10$ , find the value of ${{p}^{2}}-2p-100$ .

Answer 1

Hint: Here, the question is given in simple algebraic expression. In this question we are asked to find the value of ${{p}^{2}}-2p-100$. To find this we need to substitute the value of ‘p’ as ‘-10’ in the given equation. Then simplify it to get the answer.

Complete step-by-step answer:
Here, we need to find the value of ${{p}^{2}}-2p-100$ which is a simple algebraic expression.
An algebraic expression in mathematics is an expression which is made up of variables and constants along with algebraic operations (addition, subtraction, etc). Expressions are made of terms. They are also termed as algebraic equations.
According to the question, it is given that $p=-10$.
Now, we will put the value of p in the given equation.
i.e. ${{p}^{2}}-2p-100$
$={{\left( -10 \right)}^{2}}-2\left( -10 \right)-100$
$=\left( -10 \right)\left( -10 \right)-2\left( -10 \right)-100$
By simplifying the above equation, we get –
$=100+20-100$
By cancelling \[+100\] and $-100$ we get –
$=20$ .
Hence, the value of ${{p}^{2}}-2p-100$ is 20.

Note: Generally students get confused and make mistakes while simplifying the equations of algebraic expression while dealing with signs. They may get confused while multiplying the digits with different or same signs. They should have some basic multiplication rules of signs. Such as –
$\left( + \right)\times \left( + \right)$ multiplication of two positive $=+$
 $\left( + \right)\times \left( - \right)$ multiplication of a positive and a negative $=-$
$\left( - \right)\times \left( - \right)$ multiplication of two negative $=+$
$\left( - \right)\times \left( + \right)$ multiplication of a negative and a positive $=-$ .
Therefore, product of two same signs is positive and product of two different signs is negative.