Question

Which step has the mistake in solving for roots?

2x^2 – 7x – 3 = 1

Step 1: 2x^2 – 7x – 4 = 0

Step 2: x^2 – 7x – 8 = 0

Step 3: (x-8)(x+1) = 0

Step 4: (x-8/4)(x+1/4) = 0

Step 5: (x-2)(4x+1) = 0

Step 6: x – 2 = 0 4x + 1 = 0

Step 7: x = 2 x = -1/4

One of these steps is incorrect. List the step that is incorrect, then finish the problem correctly.

Answer 1

Explanation:

2x² - 7x - 3 = 1

Step 1: 2x² - 7x - 4 = 0

Step 2: incorrect.

Use Quadratic Formula to solve for roots.

x = [7 ± √(7² – 4·2(-4))] / [2·2]

 = [7 ± √81] / 4

 = [7 ± 9] /4

 = -0.5, 4