Write an expression for the area of a rectangle in terms of x

Ensure the student understands that the two expressions are equivalent. Examples of Student Work at this Level The student: Questions Eliciting Thinking What does x represent in this problem? Verify that the student understands the difference between mathematically equivalent and looks the same.

Ask the student to explain the relationship between the quantities represented and how the different forms can reveal different information about the problem context.

The two expressions are equivalent. Instructional Implications Make sure the student understands the terms expression and equivalent expression. Does not give a specific explanation.

What are the coefficients and why are the coefficients added and not multiplied? What is the result? Guide the student to give a justification for equivalence by referencing properties of operations e. Can you explain the differences? What terms can be combined in the first expression?

Where did the numbers come from? Questions Eliciting Thinking What do the numbers and variables represent in the second expression? Focuses on trying to find a value for x.

What do the variables represent in each expression?

Rectangle Expressions

Got It The student provides complete and correct responses to all components of the task. Include an explanation of the rationale for writing expressions in equivalent form.

The student cannot relate the expressions to specific aspects of the context of the problem. Examples of Student Work at this Level The student explains: Provide additional opportunities for the student to rewrite expressions in equivalent forms. Moving Forward The student cannot identify equivalent expressions.

Explains how to find the perimeter of a rectangle. What is this expression telling you to do to the width of the rectangle? What do the numbers represent? Do you have enough information to solve for x? Have the student explain which expression is preferred for this purpose and why.

Questions Eliciting Thinking Why do you need to find the value of x? What does it mean to combine like terms? Could you have found the perimeter of this rectangle if you only knew its width?

Can you simplify the first expression by combining like terms?

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Then ask the student to find the length of the rectangle and explain his or her strategy. If needed, review how the perimeter of a rectangle is calculated. Ask the student to describe what the expression indicates about using the width to calculate the perimeter.

Explain the relationship between the two expressions using appropriate mathematical vocabulary.Since we have a rectangle, you know that opposite sides are the same length, so an expression for the perimeter could be written as follows: P = 3 + 5 + 3 + 5 I started at one of the sides that was 3 units long, and went around the rectangle.

Aug 15,  · 1) The area of a rectangle is found by the formula L x W, so just plug in the values for length and width (x + 2)(x) 2) Write the area on one side of the equality sign and the known value for the area on the other sideStatus: Resolved.

So if your rectangle has a length of (x+3) and a width of (3x+4) then (surprise, surprise) its area is length times width: A = (x+3)(3x+4) This may be an acceptable answer. Multiplying the expressions for the measures of the sides of a rectangle gives you the area of the rectangle.

is indeed the correct expression for the product you describe and had you provided a number that represents the area of the rectangle, it would be a simple matter to set your product of sides expression equal to the given area from which it is a. Dec 09,  · The area of a rectangle is 3x²+2x The length of the rectangle is (x+3).

Write an expression in terms of X representing the width of the rectangle?Status: Resolved. Guide the student to interpret the expression 8x + 4 in terms of x, the width of the rectangle. Provide a value of x, and have the student use the expression 8x + 4 to calculate the perimeter of the rectangle.

Ask the student to describe what the expression indicates about using the width to calculate the perimeter. Have the student compare .

Write an expression for the area of a rectangle in terms of x
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