3)
(x/3)+(2/5)
(5x/15)+(6/15)
(5x+6)/15
4)
(2/x)+(3/7)
(14/7x)+(3x/7x)
(3x+14)/(7x)
5)
(x/2)+(1/3)+(x/4)
(6x/12)+(4/12)+(3x/12)
(9x+4)/12
#2- yes because both can be divided or multiplied for example 3 and 9, u can multiply 3x3 to get 9 since the dilation is 3 then yes it is similar triangles
If you want me to solve for "Y" then, the answer will be,

ir if you want me to solve for "X" instead then the answer will be,

2,6,18,54 because they have a common ratio of 3
The first interception for this function would be at (1,0) the next would be (4,0)