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1) When a quantity (variable n) in an equation is not know and you are trying to evaluate it. For example, if a banana costs 5 cents, how many can you buy for 25 cents. We solve this by saying
Let n be the number of bananas that we can buy for 25 cents, then we have
5 x n = 25 and hence n = (25/5) = 5
2) When you want to express the general term in a series. For example the arithmetic series 1, 4, 7, 10, 13, 16,.......... is really
1, (1+3), (1+6), (1+9), (1+12), (1+15).......... and in general for such an arithmetic series you can find the 100th, 223rd, 567th term without writing down the long chain of numbers. How? we see a pattern in the arithmetic series. If we represent the starting number (1 in our case) as "a"and the equal increment from one term to the next (that's how an aritmetic series is defined) as "r" then the formlua "a + (n-1)r" gives you the n-th number. Remember that in the illustration above 1 is considered the 1st term in the series, (1+3) is the2nd term, (1+6) is the3rd term and so on.
What else can I help you with?
How do you write an expression that represents the sum of a number and 12?
To write an expression that represents the sum of a number and 12, you can use a variable to represent the unknown number. For example, if you let the variable ( x ) represent the number, the expression would be ( x + 12 ). This indicates that you are adding 12 to whatever value ( x ) holds.
What is the algebraic expression for the product of 14 times a number?
Assuming you call your number "n", the expression would be "14n". You can replace "n" with whatever variable you want to use.
A letter that is used in place of a number?
Roman numerals use letters in place of numbers. An unknown variable in algebra uses a letter instead of a number.
How do you write the sum of a number and thirty - seven in an algebraic expression?
To write the sum of a number and thirty-seven in an algebraic expression, you would use the variable "n" to represent the number. The algebraic expression would be n + 37, where "n" represents the unknown number and 37 represents thirty-seven. This expression represents the sum of the unknown number and thirty-seven.
How do you write 25 less than a number for algebric expression?
To write "25 less than a number" as an algebraic expression, you would represent the unknown number as a variable, such as "x." Therefore, the algebraic expression would be written as "x - 25." This expression indicates that you are subtracting 25 from the unknown number represented by "x."
When do you need to use a variable when writing an expression?
when ther is no number
What does the variable represent in an addition or subtraction expression?
it is the number you would use to solve the problem
Nine more than a number write in pharse as an algebric expression use x for variable in your expression?
(x + 9)
What do you call replacing a variable in an expression by a number?
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
Write the phrase as a variable expression. Use x to represent "a number."The sum of a number and 138?
x + 138
What is the algebraic expression for 58 less than a number?
In this case, you'll have to use a variable. Variables are basically a symbol which stands for a number. Let's use the variable "m". You're searching for 58 less than a number. That is basically just "word form" for a number, or a variable, minus 58. So if we use the variable "m", the expression will be m-58. Remember that you can use any variable you want.
How do you write an expression that represents the sum of a number and 12?
To write an expression that represents the sum of a number and 12, you can use a variable to represent the unknown number. For example, if you let the variable ( x ) represent the number, the expression would be ( x + 12 ). This indicates that you are adding 12 to whatever value ( x ) holds.
What is the algebraic expression for the product of 14 times a number?
Assuming you call your number "n", the expression would be "14n". You can replace "n" with whatever variable you want to use.
Translate the phrase into a variable expression. Use the letter d to name the variable. If necessary use the asterisk ( ) for multiplication and the slash ( ) for division.?
Translate the following phrase into a variable expression. Use the letter d to name the variable. …7 times the distance
Explain how you know to use a variable in an addition or subtraction expression?
that we can use it
A letter that is used in place of a number?
Roman numerals use letters in place of numbers. An unknown variable in algebra uses a letter instead of a number.
How do you write ten dollars more than twice your savings as a variable expression?
we will use the variable 's' to represent your savings: 2s+10
