Question:

Consider the following sequence of steps to solve the equation: -15 + 4x + 4x2 = 0

Step 1 ⇒ 4x2 + 4x - 15 = 0
Step 2 ⇒ 4x2 - 6x + 10x - 15 = 0
Step 3 ⇒ 2x(2x - 3) + 5(2x - 3) = 0
Step 4 ⇒ (2x + 5)(2x - 3) = 0
Step 5 ⇒ x = -3/2 or x = 5/2

A. Explain why Step 1 is valid using properties of the real number system.
Show possible intermediate steps to support your explanation.

A. Explain why Step 4 is valid.