Question

Raj is 3 years older than Zia. The sum of the squares of their ages is 369. How old are they?

Answer 1

Let
x--------------> ages of Raj
y--------------> age of Zia

we know that
x=y+3-------------> equation 1
x²+y²=369-----------> equation 2

I substitute 1 in 2

(y+3)²+y²=369----------> y²+6y+9+y²=369---------> 2y²+6y-360=0
2y²+6y-360=0
using a graph tool-----------> to calculate the quadratic equation
see the attached figure

the solution is
y=12
x=y+3--------> x=12+3--------> x=15

the answer is
Raj is 15 years old
Zia is 12 years old