Rob is twice joshua's age. nick is 5 years older than joshua. the sum of all their ages is 45. how old is nick?

Given

Rob is twice Joshua's age

Nick is 5 years older than Joshua.

sum of all their ages is 45.

Find the age of nick.

To proof

As given

Rob is twice Joshua's age

let  Joshua's age = x

than Rob age = 2x

Nick is 5 years older than Joshua.

Nick age = 5 + x

sum of all their ages is 45

than the equation becomes

Joshua's age + Rob age + Nick age = 45

put the value

x + 2x + 5 + x = 45

4x = 40

x = 10

Joshua's age = 10 year

than Rob age = 20 year

Nick age = 5 + 10

                = 15year

Hence proved

the first one is x^2+2x+2

the second one is x^2+4

the last one is x^2-4x+8