Question

The work of a student to find the dimensions of a rectangle of area 8 + 12x and width 4 is shown below:

Step 1: 8 + 12x
Step 2: 4(2) + 4x(2)
Step 3: 4(4 + 8x)
Step 4: Dimensions of the rectangle are 4 and 4 + 8x
In which step did the student first make an error and what is the correct step?
Step 2; 4(2) + 4x(2)
Step 2; 4(2) + 4(3x)
Step 3; 4+ (4 + 8x)
Step 3; 4 + (48X)

Answer 1

Explanation:

Option 3rd is correct

Explanation:

Area of a rectangle is given by:

where

l is the length and w is the width of the rectangle

As per the statement:

To find the dimensions of a rectangle of area 8 + 16x and width 4 .

Step 1.

Step 2.

Step 3.

Step 4.

Dimensions of the rectangle are 4 and 2+ 4x

Since, the student make an error in the Step 2

Therefore, the correct step is, 4(2) + 4(4x)