1+y^2-2y=1-2y+y^2= (1-y)^2
64-16b+b^2=8^2-16b+b^2= (8-b)^2
9x^2-24xy+16y^2=3^2* x^2-24xy+16y^2= (3x-4y)^2
1+y^2-2y=1-2y+y^2= (1-y)^2
64-16b+b^2=8^2-16b+b^2= (8-b)^2
9x^2-24xy+16y^2=3^2* x^2-24xy+16y^2= (3x-4y)^2