Finding Y-Intercepts of Functions

Rees explains how to graph a quadratic function by first finding its Y-intercept. She describes the Y-intercept as the point where the graph intersects the Y-axis, which occurs when x equals zero. Rees demonstrates the calculation by substituting x with zero in the quadratic equation y = x^2 + 2x - 15, simplifying it to find that the Y-intercept is at the point (0, -15).

What is the purpose of finding the Y-intercept before graphing a quadratic function?

• To identify the maximum point of the graph

• To find where the graph crosses the Y-axis

• To calculate the vertex of the graph

• To determine the slope of the graph

What value should x be set to in order to find the Y-intercept of a function?

• -1

• 0

• 2

• 1

Why is it important to substitute x with 0 when finding the Y-intercept?

• To find the slope of the line

• To determine the x-intercept

• To locate where the graph crosses the Y-axis

• To calculate the maximum value of the function

When substituting x with 0 in the function y = x^2 + 2x - 15, what is the resulting equation?

• y = -15

• y = 0

• y = 2

• y = 15

What is the Y-intercept of the quadratic function y = x^2 + 2x - 15?

• (0, 15)

• (0, 2)

• (0, -15)

• (0, 0)

What does the Y-intercept represent in the context of graphing a function?

• The point where the graph crosses the X-axis

• The lowest point on the graph

• The point where the graph crosses the Y-axis

• The highest point on the graph