Question

What is the x intercept od this piecewise function? A) (0,2) B) (2,0) C) (0,4) D) (4,0)​

Answer 1

Answer: Choice B) (2,0)

======================================

Set the first piece equal to zero and solve for x

x^2 - 4 = 0

x^2 = 4

x = sqrt(4) or x = -sqrt(4)

x = 2 or x = -2

Keep in mind that the first piece y = x^2-4 is only graphed when x = 2 or larger, so we ignore x = -2. This is one x intercept, but there may be more. Let's check the other graph to see what we get.

----------

Set the second piece equal to zero and solve for x

x-2 = 0

x-2+2 = 0+2

x = 2

We get the same result as above in the prior section. Because of this, the two pieces connect at this junction point.

The x intercept x = 2 leads to the location (2,0). The x intercept always occurs when y = 0.

The graph below shows this.

side note: the red piece y = x^2 - 4 looks linear, but it's actually not a straight line. It's just a really stretched out curve.