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Contents
Factorisation of Quadratic Polynomials
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Evaluation of Algebraic Expressions Given a number for the variable, substitute the variable with it.
Kath ordered 5 packets of rice and 10 packets of milk from ABC Provision Store. The owner was not in and John took the order. He did not know the prices of the items, so he represented the amount by the equation (5m+10r) where m stands for milk and r for rice. Later, he found out that m=2 and r=5. He evaluated the expressions like this: 5m+10r=5 x 2 +10 x 5 =10+50 =60 Thus, Kath has to pay $60.
Example 1:
 Evaluate the
following by taking a= 2, b=4 and c=3.
a(b + c)
 a(b
+ c)=2(4
x 3)
=14
Example 2:
Verify the following by taking a=2, b=-9 and c=3
a(b - c)=ab - ac
a(b
- c)= ab - ac
LHS= 2(-9 - 3)
=
2(-12)
=-24
RHS= 2 x(-9)-2 x 3
=-18 -
6
=-24
a(b-c)=ab - ac since LHS = RHS.
Example 3:
Given p=3,
q=½, x=-4 and y=-½, calculate
5px+3qy2
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