chapter 3......
3.1 Algebraic Terms In Two Or More Unknowns
1. An algebraic term in two or more unknowns is a product of the unknowns with a number.
Example:
5xy = 5 x x x y
Therefore, 5xy is the product.
2. The term mª implies that the unknown m is multiplied a times by itself. This is known as repetitive multiplication of an unknown.
Example:
k³ = k x k x k
k is multiplied 3 times.
3. Normally, the product of the unknowns number is expressed without the mutiplication
symbol.
6pqr = 6 x p x q x r
4. The coefficient of an unknown in an algebraic term is the factor of the algebraic term.
Example:
2xy
2 is the coefficient of xy
3.2 Multiplication and Division of Two or More Algebraic Terms
1. The product of two algebraic terms can be found by multiplying the numbers and the same
unknowns separately.
Example 1:
3mn x 4mn²p = 12m²n³p
2. The quotient of two algebraic terms can be found using the cancellation method.
Example 2:
40xy²z ÷ 8xy = 5yz
→we can cancel x and y
3.3 Concept of Algebraic Expressions
1. Algebraic expression can be written using letter symbols.
2. In algebra, letters are used to represent unknowns and numbers.
Example 1:
Assume a number, we can assume it by x.
Then we multiplied this number by 8 → 8x
After that, we add 10 from the term → 8x + 10
So, now we can express the above given as 8x + 10.
3. An algebraic expression consists of two or more algebraic terms combined by addition or
subtraction or both.
4. Combinations of algebraic terms in two or more unknowns will produce algebraic expression
in two or more unknowns.
Example 2:
Algebraic expression in two unknowns → 3mn - mn; 10xy + 2xy
Algebraic expression in more than two unknowns → 2ab - 3mn + 4xy; a² + 2ab +cd³.
5. Only expression with similar term can be adding or subtracting the coefficient of the
unknowns
6. To simplify an expression that consists of a few like and unlike terms:
(i) rearrange and group the like terms
(ii) then, add or substract the coefficient of the unknowns
Example 3:
5mn + 4mn = 9mn
* This term can be added because the unknown is same (like terms)
Example 4:
6mn-4pq = 6mn - 4pq
* This term can not be subtracted because the unknowns is different (unlike terms)
7. The expression can be evaluated when the unknowns is substituted with the given number.
Example 5:
Find the value of 3mn² + 2p²q - mp; given that m=1, n=2, p=-1 and q=-2
Firstly, we subtitute all the unknowns into the expression, its becomes:
3(1)(2)² + 2(-1)²(-1) - (1)(-1)
=12 - 2 + 1
= 11 * The answer is 11 after the calculation
3.4 Computations Involving Algebraic Expressions
1. Multiplying algebraic expression by a number
To simplify the product of an algebraic expression with a number, each term in the expression
must be multiplied by the number:
Example 1:
Simplify 8(3mn - 4xy)
= 24mn - 32xy
2. Dividing algebraic expession by a number.
To simplify the quotient of an algebraic expression with a number, each term in the
expression must be divided by the number:
Example 2:
Simplify (4ab² - 8c³d + 12ef) ÷ 2
= 4ab²/2 - 8c³d/2 + 12ef
= 2ab² - 4c³d + 6ef
3. Adding two algebraic expression.
To find the sum of two algebraic expression, we can simplify the algebraic expression using
the following method:
→Remove brackets and groups the like terms.
→Find the sum or difference of the like terms.
Example 3:
Simplify (2mn + 4p²) + (3mn - 5p²)
= 2mn + 4p² + 3mn - 5p²
= 2mn + 3mn + 4p² - 5p²
= 5mn - p²
4. Subtracting two algebraic expressions.
To find the difference between two algebraic expressions, we can simplify the algebraic
expressions, we can simplify the algebraic expressions using the following methods:
→Remove brackets and change the symbols of the terms in the subtracted algebraic
expression. Then, group the like terms
→Find the sum or difference of like terms.
Example 4:
Simplify (4m²n - 5pq) - (mn - 2pq - 6m²n)
= 4m²n - 5pq - mn + 2pq + 6m²n
= 4m²n + 6m²n - 5pq + 2pq - mn
= 10m²n - 3pq - mn
Tutorials (2):
1. (-4a²b) ÷ 3b²c² x 9ac 2. 3pq x 6rp²q
3. Given that p=-3 and q = 2, 4. 3mx² - 8n²y + (-4mx²) - n²y
evaluate p² + (-pq²) - p²q²
5. -15(-x²yz² + 2pq² - 3mn) = 6. (p³q x -9pq) ÷ 3p
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