Find the greatest common factor of 6ab, 3a

Two variables, x and y, vary inversely, and x=12 when y=4. what is the value of y when x=3?

Atransformation t : (x,y) (x-5,y +3) the image of a(2,-1) is

Do one of the following, as appropriate: (a) find the critical value z subscript alpha divided by 2 , (b) find the critical value t subscript alpha divided by 2 . 99%; nequals 17; sigma is unknown; population appears to be normally distributed.