Page 53 - Math Smart - 7

An algebraic expression is made up of constants, variables, operation signs
(+, X, -r), and can include brackets. An algebraic expression has no equal
signs. 3, 7, 4 A term with no
variables is called a
The following are some examples of algebraic expressions.
constant.
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2n n + iy + y-2x + x,y.z A variable is a changing
3
7
quantity that may have
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3y -i-2x~w+ 7 y + any one of a range of
possible values. The
letters used are written
term term term in alphabetical order.
3x 0 2y 0 9xy 0 2n, y, vv The parts that are
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added together are
the terms of the
expression.
coefficient variable coefficient- constant
2, 3, -1 The numerical part
of a term is called its
operation sign
coefficient. It is usually
Example 4 written before the
variable.
Write each of the following as an algebraic expressions.

O Take a number and multiply it by 2. Take another number and multiply it
by 5. Add the two results together. Subtract 10 from the sum.

Solution
Let the two numbers be'a and b respectively. Let us look at each operation.
Think and Share
Take a number and multiply it by 2. 2a
How does it work?
Take another number and multiply it by 5.
Think of a number.
Add these two answers together. 2a + Sb
Add 10.
Subtract 10 from the sum. 2a + Sb - 10 Double the result.
Subtract 6.
Divide by 2.
© Take a number and multiply it by another number. Multiply the result
Subtract the number you
by 13. Add another number to the result. Multiply the result by 3.
started with.
Solution The result will always
be 7.
Let the three numbers be m. n and p respectively. Let us look at each operation.
How does it work? Use
Take a number and multiply it by another number, mxn = mn algebraic expressions to
Multiply the answer by 13. 13 xmn = 13mn explain why.
p
Add another number to the answer. 13mn +
Multiply the answer by 3. 3(13mn+p)

o