Articles

Solving Systems of Equations by Substitution Course

Consider the system of equations
\( x\  – \ y\ = \ 1\ –\ 2\ x\  +\  y \ = \ 6\)
Substitute \(\ x\  = \ 1\  –\ y\ \) in the second equation
\( -2(\ 1\ -\ y\ ) + y = 5 y = 2\) 
Substitute\(\ y\  = \ 2\  in \ x\  = \ 1\  +\  y\)
\(\ x\  = \ 1\  + \ 2\  = \ 3\)
Example:
\( –\  2\ x\  –\  2\ y\  = -\ 13\)
\( –\  4\ x\  +\  2\ y\  = \ 10\)
\((\ 0\ .\ 5\ ,\ 6\ )\)
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Whole Number Multiplication and Division Course

Multiplication:
– Learn the times tables first!
– For multiplication, line up the numbers you are multiplying.
– Start with the ones place.
– Continue with other digits
– A typical division problem:
Dividend \(  \div \) Divisor\(  = \) Quotient
Division:
– In division, we want to find how many times a number (divisor) is contained in another number (dividend).
– The result in a division problem is the quotient.
Example:
\(\ 200\  \times \ 90\  = \ 18,000\)
\(\ 18,000\  \div \ 90\  = \ 200\)
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