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Algebra |
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Algebraic Properties of Real Numbers
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The basic algebraic properties of real numbers a,b and c are:
1. Closure: a + b and ab are real numbers 2. Commutative: a + b = b + a, ab = ba 3. Associative: (a+b) + c = a + (b+c), (ab)c = a(bc) 4. Distributive: (a+b)c = ac+bc
5. Identity: a+0 = 0+a = a 6. Inverse: a + (-a) = 0, a(1/a) = 1 7. Cancelation: If a+x=a+y, then x=y 8. Zero-factor: a0 = 0a = 0 9. Negation: -(-a) = a, (-a)b= a(-b) = -(ab), (-a)(-b) = ab
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Algebraic Combinations |
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Factors with a common denominator can be expanded:

Fractions can be added by finding a common denominator:

Products of fractions can be carried out directly:

Quotients of fractions can be evaluated by inverting and multiplying:

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Algebraic Equations |
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The role of a basic algebraic equation is to provide a formal
mathematical statement of a logical problem. A first order algebraic
equation should have one unknown quantity and other terms which are
known. The task of solving an algebraic equation is to isolate the
unknown quantity on one side of the equation to evaluate it numerically.
Using x as the unknown and other letters to represent known quantities,
consider the following example equation:
The strategy for solving this equation is the repeated application of
the golden rule of algebra to collect like terms and
isolate the quantity x on one side of the equation.
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Algebra Practice Equation |
Solving a basic algebraic equation involves repeated
applications of the golden rule of algebra to isolate
the unknown quantity on one side of the equation. Using x as the unknown
and other letters to represent known quantities, consider the following
example equation:

Note that there are a number of circumstances where a solution does
not exist. If b=0, then the first term is infinite, so the calculation
defaults to the value b=1 if no value of b is entered in order to avoid
this condition for an infinity. Any set of values for which a=bd will
also give an infinity, as can be seen from the expression for x above.
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Golden Rule of Algebra |
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Any mathematical operation can be performed on one side of an
equation so long as the identical operation is performed on the other
side of the equation.
The solution of basic algebraic equations is
accomplished by applying this rule repeatedly in order to isolate the
unknown quantity and evaluate it. The application of this rule -
proceeding by doing clear symmetric operations on the two sides of an
equation - can help avoid most common mistakes in solving algebraic
equations.
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