We have the parent function: y = x³ and we have to choose the correct answer to the question: which equation describes how is this function vertically stretched by a factor of 4. y = x³ + 4 → The parent function is moved vertically 4 units up. y = ( x + 4 )³ → The parent function is moved horizontally 4 units left. y = x^4 → This is a different function. Answer: C ) y = 4 x³.
