RE: Worksheet 3

Question

funtion is-x^2-4x-5

answer questions below

a.Domain(interval notaion)

b.Range(interval notation)

c.The function is Increasing on the interval(answer in interval notaion)

   or the function is never increasing

d. the function is Decreasing on the interval(answer in interval notation)

    or the function is never decreasing

Answer 1

x^2 -4x -5

 

We know it is a parabola

 

we know it faces up

 

we know the zeros or factors are "-" and a "+" and the "-" is greater

 

it factors to: (x-5)(x+1)

 

the zeros are x=5, -1 this is where the parabola crosses the x-axis and the y is zero

 

take the differential to find the vertex 2x-4 = 0, x=2 therefore y= -9 The lowest point is (2,-9)

 

the domain -s (-OO, OO)

 

the range is [-9, OO)

 

It decreases in Y from -OO to 2 on the x

 

It increases in Y from 2 to +OO on the x