Question

A student is asked to calculate the value of 133 using the identity (x + y)3 = x3 + 3x2y + 3xy3 + y3. The student's steps are shown below.

Step 1: 133 = (10 + 3)3

Step 2: = (10)3 + 3(10)2(3) + 3(10)(3)2 + (3)3

Step 3: = (1,000) + (180) + (270) + (27)

Step 4: = 1,477

The correct answer should be 2,197. In which step did the student make his first error?

Answer 1

Step 1.

Explanation:

You can't multiply sum of 2 random digits to the power of 3.