В скобках
(y+3)/(y-3) -y²/(y-3)(y+3) =
=((y+3)(y+3) -y²) /(y-3)(y+3) =
=(y²+6y+9 -y²) /(y-3)(y+3) =
=(3(2y+3)) /(y-3)(y+3)
умножение
((y+3)*3(2y+3)) /(2y+3)*(y-3)(y+3) =
=3 /(y-3)
IABI=√(1+3)²+(-2-y)²)
√(16+(-2-y)²)=5
16+(-2-y)²=25
(-2-y)²=9
1) -2-y=3 2) -2-y=-3
y=-5 y=1
A(-3 ;-5) или А(-3; 1)
Привести к общему знаменателю. Домножим 7 на 1+3a