Square and Square Roots
 

Square of a binomial for KS3



The square of the number is already known.


Example

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Let's see what the square of the binomial looks like:


Example

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Let’s take a look at how we calculate it below.


Calculating the square of a binomial



We get to the square of a binomial by the same procedure as multiplying the polynomials. We square a binomial by multiplying it by itself.


Example

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When squaring a two-term, we got a three-term. Which are the product of two terms:




is transformed into the sum of three terms:




The process of transforming a product into a sum is called expansion.


From the above example, we can understand the rule for calculating the square of a binomial. As a result, we see that for a three-term:

  • The first term of the trinomial is obtained by squaring the first term of the initial binomial;

  • The second (intermediate) term of the trinomial is the sum of two identical products - the products of the first and second term of the binomial;

  • The third term of a trinomial is obtained by squaring the second term of the binomial.


When we calculate the square of a two-term, we always get a three-term.



General formula for squaring a binomial



Derive a general formula for squaring any binomial. Square the binomial , where a and b can be arbitrary numbers (even negative ones).


Let's calculate:



Since the numbers a and b are arbitrary numbers, the above result applies generally, in any case. a represents the first term of the binomial, b the second term. In words, we can form a rule for the square of a binomial as:




That is, in mathematical form with a form (formula) for the square of a binomial.


We get the rule for calculating the square of a binomial:




Transforming the product of the terms into the sum or difference of the terms is called factorization.



Let’s look at another example where one of the numbers is negative.


Example

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If one of the terms in a two-term is negative, then the result is a three-term that has the second term negative.


material editor: Amarachi Akobundu