Question

How do you write algebraic expressions to model quantities

Answer 1

To write algebraic expressions to model quantities is you base the algebraic expressions or mathematical values declared in words by the manner of how the sentence illustrates the said problem. For example, one minus a number is the difference of zero shall be
1. 1 – n = 0.
Other same examples, John bought 25 apples while Julia bought only 15 from the market. If Niccole bought twice as much as Julia’s, how many was Niccole’s apples?
1.      You state the problem by the sequence of the said problem and understanding the possible structure.
2.      Solution will be Julia = 15 apples Niccole = 2Julia  
Hence, 2Julia = 2(15) = 30 apples.

Answer 2

The correct answer is:

We use a variable to represent any unknown value.  Then we look for key words to tell us what operations have been performed.  For example, "sum" indicates addition, "product" is multiplication, "difference" is subtraction and "quotient" is division.  "Is" means equals to.  We pay careful attention to the order in which things are listed in the problem, as we want to write them in the same order algebraically.

For example:

Two more than 3 times a number is 23.

The unknown number will be x.
3 times a number would be 3*x = 3x.
Two more than this means two added to this, which gives us 3x+2.
This "is" 23, so it equals 23:  3x+2=23.