Multiples of 15 are: 15,30,45,60,75,90,105,120,135,150,165,180,195,210,225,240,255,270,285,300,315,330,345,360,375,390,405,420,435,450,465,480,495,510,525,540,555,570,585,600,615,630,645,660,675,690,705,720,735,
On the left-hand side of the equation 4 will cancel-out 4, thus the equation becomes;
3x + 5 = 16x
subtract 3x from both-side of the equation
16x - 3x = 5
13x = 5
Divide both-side of the equation by 13
=
(On the left-hand side of the equation 13 at the numerator will cancel-out 13 at the denominator while on the right-hand side of the equation 5 will be divided by 13)