Page 146 - ICSE Math 8

AT A GLANCE

¾ A symbol having a fixed value is known as a constant and a symbol that can take different values is
known as a variable.

¾ Terms having the same literal factors are known as like terms otherwise they are unlike terms.
¾ Any factor in a term is known as the coefficient of the product of the remaining factors.
¾ A single term or a combination of two or more terms connected by plus (+) addition or minus (–) signs
is known as an algebraic expression.
¾ An algebraic expression which consists of only one term with non-negative integral powers of variables
is known as a monomial.
¾ An algebraic expression having two terms with non-negative integral powers of variables is known as
a binomial.
¾ An algebraic expression having three terms with non-negative integral powers of variables is known as
a trinomial.
¾ An algebraic expression in which the exponents of a variable are non-negative integers is called a
polynomial in one variable.
¾ An algebraic expression in which the exponents of two or more variables are non-negative integers is
called a polynomial in two or more variables.
¾ The degree of a polynomial in one variables, is the highest power of the variable.

¾ The degree of a polynomial in two or more variables is the highest sum of the powers of the variables.
¾ A polynomial is said to be linear, quadratic, cubic or quartic, if its degree is 1, 2, 3 or 4 respectively.

MENTAL MATHS

1. Fill in the blanks.
2
2
(a) x y and y x are __________ terms.
1
3
3
7
(b) The degree of the polynomial a + a – a is __________.
7
2
3
(c) The algebraic expression 2a + b – a b, is a __________ in __________ variables.
(d) In the term 4a, __________ is the numerical factor and __________ is the literal factor.
3
3
2
2. For the polynomial, l m – lm + lm – 25, answer the following questions.
(a) What is the number of terms in the expression?
2
(b) What is the coefficient of l ?
(c) What is the degree of the given polynomial?
PRACTICE TIME

2
2
1. What should be added to 3p + 8pq – 5 to get 9p – 5pq – 4?
3
2 4
3
2 4
2. The sum of two expressions is x y + x y – 5. If one of the expressions is 2x y – x y – 3, find the other
expression.
3. The sides of a triangle are (3x + 2y) units, (x – 2y) units and (4x – 2y) units. Find the perimeter of the
triangle.
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