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                Example 3: Write the degrees of the following algebraic expressions:

                                                                     1
                                                                                        3
                                                                                                               3
                                                                                                       4 4
                                                            2
                                                                                 3 2
                           (a)  12x + 7              (b)  5x  – 6x +       (c)  m n  + n m        (d)  p q  – 7p  – 2pq 2
                                                                     3
                Solution: (a) In the expression 12x + 7, the highest power of the variable x is 1 in term 12x. So, the
                               degree of the given polynomial is 1.
                                                              1
                                                                                                                       2
                                                     2
                           (b)  In the expression 5x  – 6x +  , the highest power of the variable x is 2 in term 5x .
                                                              3
                               So, the degree of the given polynomial is 2.
                                                            3
                                                     3 2
                           (c)  In the expression m n  + n m, the highest power of polynomial is 3 + 2 = 5 in term
                                 3 2
                               m n . So, the degree of the given polynomial is 5.
                                                    4 4
                                                                  2
                                                           3
                                                                                                                 4 4
                           (d)  In the expression p q  – 7p  – 2pq , the highest power is 4 + 4 = 8 in the term p q . So,
                               the degree of the given polynomial is 8.
                Types of Polynomials
                               Constant Polynomial          Linear        Quadratic          Cubic        Biquadratic
                                                          Polynomial     Polynomial       Polynomial       Polynomial
                 Definition   A polynomial consisting    A polynomial  A polynomial      A polynomial     A polynomial
                              of a constant term only      of degree      of degree 2    of degree 3 is    of degree 4
                                is called a constant       1 is called    is called a    called a cubic     is called a
                              polynomial. The degree        a linear      quadratic       polynomial.      biquadratic
                             of a constant polynomial    polynomial.     polynomial.                      polynomial.
                                      is zero.
                                                                            2
                                                                                                                 3
                                                                                              2
                                                                                                            4
                                                                                         3
                                                                                                                      2
                 Examples             8, –29, 6          5x – 1, 3 + 2x  6x  – 5x + 1,  x  – 7x  + 3x + 1,  5x  – 7x  + 4x
                                                                                              3
                                                                            2
                                                                          2y  – 2y + 5      x  – 5x          – x + 8
                Addition and Subtraction of Algebraic Expressions
                Addition of Algebraic Expressions
                While doing addition, we add the like terms and write the unlike terms as they are. So, when we
                do the addition, we write each expression to be added in a separate row and write the like terms
                one below the other and add them.
                For example, add 8x + 4y  + 3 and 7x – 4.
                                           2
                                          2
                                 8x  +  4y   +  3
                                 7x         –  4  (Write the like terms one below the other)

                               15x  +  4y   –  1
                                          2
                Thus, the sum of two or more like terms is a like term whose numerical coefficient equals the sum
                of the numerical coefficients of all the like terms being added and the literal factor is the same as
                the literal factor of the given like terms.
                Subtraction of Algebraic Expressions


                To subtract an algebraic expression from another, we change the signs (from ‘+’ to –’ and ‘–’ to ‘+’)
                of all the terms of the expression which is to be subtracted and then add the two expressions.

                                                                  197                                 Algebraic Expressions
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