Quadratic Question Need Help! (1 Viewer)

[kevinsta]

y=x^2-6x+8
Factor and sketch the quadratic. Hence find the range of each function (i) with unrestricted domain. (ii) with domain x is greater than or equal to 5, (iii) with domain 0 is less than or equal x which is less than or equal to 5.

Any help would be appreciated

 

[Study notes]

for (i) find the vertex.

the x coordinate = -b/2a =- (-6)/2(1) = 3

sub back into y = x^2....

y = -1

so vertex at (3,-1)

so if domain is unrestricted, the range is y=>-1 (which u can see more clearly if u sketched the right parabola)

if the domain x is greater than or equal to 5, sub 5 into the original equation.

y = 3

so range is y=>3


I'm sure from that u can figure the third part