if the radius of a circle is 3cm and 5x+1 represents the length of the diameter how do i write an equation for x

Question

i am in 7th grade and i learned this a while ago and am now doing corrections and i need full steps on how to do it

Answer 1

Given, diameter = 2*radius, we can then set them equal to each other using this simple formula.

 

Knowing that the radius is 3cm and 5x+1 is the diameter we then can say that:

2*3        = 5x + 1
2*radius = diameter

 

Therefore, 6   =   5x +1

                -1            -1      subtract by 1 on each side

 

                5   =   5x

                /5  =   /5           divide by 5 on each side

            1cm   =   x             your solution