A thorough explanation of the idea followed by the demonstration of the process by
the teacher may enable the child to understand the idea.
- Subtraction of polynomials
Subtraction among two polynomials can be carried out by subtracting the corresponding
terms of one polynomial from the other.
Eg. :Let P(x) = 2x^2 + 5x + 10
Q(x) = x^2 + 3x + 7
Then P(x) – Q(x) = (2x^2 + 5x + 10) – (x^2 + 3x + 7)
= (2x^2 – x^2 ) + (5x – 3x) +(10 – 7)
= x^2 + 2x + 3
The process followed in addition can be followed for subtraction also.
- Multiplication of polynomials
The product of two polynomials can be found by applying the distributive law and
also the law of indices.
Eg. : Find the product of 5x^2 – 3x +5 and 2x -4
Therefore, (5x^2 – 3x +5)(2x – 4) = 10x^3 – 6x^2 + 10x – 20x^2 + 12x - 20
= 10x^3 – 26x^2 + 22x - 20
A tactile diagram depicting the numbers may be helpful for the child to understand
the sequence of the multiplication.
Another Method : Detached coefficient method
(5 – 3 + 5) (2 – 4)x^2 xx^3
2
1
4 5 6