Identifying the Y intercept from a Graph

Graph
The Y intercept in the above picture is -3.

Identifying the Y intercept from a Function Rule

If y = 3x + 5, the y intercept is 5 because when x = 0, y = 3(0) + 5 = 5.

If y = 7x² + 5x -3, the y intercept is -3 because when x = 0, y = 7(0) + 5(0)-3 = -3.

If y = 2^x +4, the y intercept is 4 because when x = 0, 2⁰ + 3 =4.

Important Fact: For all the polynomial functions, the y intercept is the constant term.

CONCEPT CHECK: The y intercept of the function: x³ +5x - 9 is:

5: FINDING THE Y INTERCEPT from a GRAPH or a FUNCTION RULE