Question

Susu is solving the quadratic equation 4x2 – 8x – 13 = 0 by completing the square. Her first four steps are shown in the table.

In which step did Susu first make an error?

Step 1
Step 2
Step 3
Step 4

Answer 1

step 3

Explanation:

Answer 2

The given Quadratic equation is

`4x^2- 8x - 13 = 0\\\\4(x^2-  2 x - (13)/(4)) = 0\\\\ (x-1)^2-1^2- (13)/(4)=0\\\\ (x-1)^2=(√(17))/(4)\\\\ x-1=\pm(√(17))/(4)\\\\ x=1 +(√(17))/(4) \text{or}     x=1-(√(17))/(4)`

These are the steps to determine the roots as well as solve the quadratic equation.

You can find the mistake by looking at the procedure of solving the quadratic equation by completing the square solved above.