Question 64095
Y = SQRT(9-4X)
THE FUNCTION IS NOT DEFINED IF 9-4X UNDER RADICAL SIGN IS NEGATIVE.
HENCE 9-4X>=0
9>=4X
9/4=2.25>=X
X<=2.25
SO DOMAIN OF THE FUNCTION IS ALL REAL VALUES >=2.25...THAT IS 
(-INFINITY,2.25]