Решите уравнение (5a +2) (5a-2) -5a(5a-1)=21 3(y+2)kv +(2y-1)kv -7(y+3) (y-3)=28

1)(5a +2) (5a-2) -5a(5a-1)=21 1)25a²-4-25a²+5a=21 5a=25 a=5 2)3(y+2)kv +(2y-1)kv -7(y+3) (y-3)=28 a)kv=0 -7(y+3) (y-3)=28 y²-9=-4 y²=5⇒y=-√5  y=√5 kv≠0 3kvy+6kv+2kvy-kv-7y²+63-28=0 7y²+5kvy+35+kv=0 D=25k²v²-27(35+kv)=25k²v²-27kv-945 1)25k²v²-27kv-945<0=нет решения 2)25k²v²-27kv-945=0 y=-5kv/14 3)25k²v²-27kv-945>0 y1=(-5kv-√(25k²v²-27kv-945))/14 y2=(-5kv+√(25k²v²-27kv-945))/14