Port Said International Schools – National Section Better education for future generations Date : -------------------- Algebraic terms and algebraic expressions Definitions : [1]Variable: A variable is a letter or a symbol that represents a number Ex.: x , y , a , b , …. [2]Algebraic term: It is forms from the product of two or more factors. Ex.: 3a , 5y , x2 , 2b , …… The algebraic term 3x is consists of 2 factors 3(numerical) and x (algebraic) The algebraic term 4y2 is consists of 3 factors 4(numerical) , y (algebraic) and y (algebraic) The degree of the algebraic term: It is the sum of the indices (powers) of the algebraic factor of this term Ex.:The term 2a is 1st degree because the index of a is 1 The term -7x2 is 2nd degree because the index of x is 2 The term 6a2 b is 2nd degree because the sum of the indices of the two symbols a and b is 3 Important note: Any number is an algebraic term of zero degree Ex: The number 4 is an algebraic term of zero degree because it can be written in the form : 4 × xzero where xzero = 1 [3] Algebraic expression: It consists of an algebraic term ( monomial ) or more. Ex.: 3y is an algebraic expression consists of one term 3y + 5x is an algebraic expression consists of two terms 3y + 5x + 6 is an algebraic expression consists of three terms 3y + 5x -3xy + 6y is an algebraic expression consists of four terms Math Department (monomial) (binomial) (trinomial) (quadrnomial) Page 1 of 4 The degree of the algebraic expression: It is the highest degree of the terms forming it. Ex.: The algebraic expression : 5x – 3 is of the 1st degree because 5x is the term of the highest degree . The algebraic expression : 7x2 + 3x – 5y is of the 2nd degree because 7x2 is the term of the highest degree . The algebraic expression : 4ab + 2a2b2 + b is of the 4th degree because 2a2b2 is the term of the highest degree . Book P: 32 Math Department Page 2 of 4 Like algebraic terms Algebraic terms are similar if the symbols forming its factors are similar and the indices of these symbols are similar Examples of like terms: 2a , 4a , -6a 3x2 , 4x2 , -2x2 2x2y , 4yx2 , - 5x2y Examples of unlike terms: 2x , 3x2 , 4x3 (their indices are different) 2 2 4x , 5xy , -y (their symbols are different ) Adding and subtracting like terms When adding or subtracting like terms , we add or subtract the coefficients of these terms while the algebraic factors stay as they are Ex.: Add: 5a + 3a + a = (5+3+1) a = 9a 7ab2 +(-2b2a) + 4ab2 + b2a = [ 7 + (-2) + 4 + 1 ] ab2 = 10ab2 Subtract 5xy from 7xy 7xy – 5xy = (7 – 5 ) xy =2xy 3 Subtract-3x y from -2yx3 -2yx3 – ( -3x3y ) = (-2 + 3 ) yx3 = yx3 Simplifying the algebraic expression: The simplest form of the algebraic expression means all its terms are unlike , so we will put it in the simplest form by adding like terms using commutative and associative properties. Ex.: Simplify: 6x + 7y + 4x – 3y = 6x + 4x + 7y – 3y = (6x + 4x ) + ( 7y – 3y ) = 10x + 4y Math Department ( commutative ) ( Associative ) Page 3 of 4 Book P: 34 Math Department Page 4 of 4