If you expand the square, you have

Simplify the right hand side:

Cancel the -3x appearing on both sides:

Multiply both sides by 4:

Consider the square root of both terms (using the doubles sign):

6/9 (2/3) and 2/3. Hope this helps you.
464 divide by 16 is 29. So y would be 29
Diana's age=21 years
Carmen's age=x years
Andrew's age=2x years
21+x+2x=45
21+3x=45
3x=45-21
3x=24
x=24/3
x=8
2x8=16
Carmen is 8 years old and Andrew is 16 years old. Hoped that helps:)