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(4) + 4(8x)
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?

Answer 1

The second step is wrong
As 12/4 is not 8 but 3

The correction steps are:

4(4) + 4(3x)
= 4(4+3x)
The dimensions are 4 and 4+3x