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A variable is a letter that represents a number. An expression that contains at least one variable is called variable expression, also called algebraic expression. A variable expression has one or more terms. A term is a number, a variable, or a product of numbers and variables. For example,

3(x^2)y + 2xy + x - 7 is a variable expression, where you have 4 terms.

When working with variable expression, you often use the substitution principle:

If a = b, then a may be replaced by b in any expression.

The set of numbers that a variable may be represent is called replacement set, or domain, of the variable. To evaluate a variable expression, you replace each variable with one of its values and simplify the numerical expression that results.

Example: Evaluate the expression 2x - 4y for x = 5 and y = -9.

Solution:

2x - 4y

= 2(5) - 4(-9)

= 10 + 36

=46

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15y ago
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Marie Johnson

Lvl 1
3y ago
wait so what is it called tho

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Q: What do you call replacing a variable in an expression by a number?
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Related questions

What do you call replacing a variable in an expression by a number and simplifying the result?

That is called 'solving'.


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What do you call replacing a variable in an algebraic expression with a quaintity?

I think it is called "replacing" or "substitution".


What do yo call replacing a variable in a algebraic expression with a quantity?

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What do you call replacing a variable in an in a algebraic expression with a quantiy?

When you replace a variable with a quantity, it is called a substitution.


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What do you call a number that stands alone in an equation?

In an equation, a number that stands alone is called a constant. It is a fixed value that does not change during the equation or its solution.


What do you call a number that multiplies a variable?

A coefficient is a number that multiplies a variable.


What is a number that has no variable attached to it?

We call a number that has no variable attached to it, a constant. A number attached to a variable, as in 3x, is called a coefficient.


How do you evaluate an expression?

You have to substitute a value for the letter variable in the expression. This is what we call evaluating the algebraic expression. An example would be 3x+1=7, when x=2.


How do you evaluate an algebraic expression?

You have to substitute a value for the letter variable in the expression. This is what we call evaluating the algebraic expression. An example would be 3x+1=7, when x=2.