Which equation describes how the parent function, y=x^3, is vertically stretched by a factor of 4?
y=x^3+4
y=(x+4)^3
y=4x^3
y=x^4

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.

C ) y = 4 x³.