Решите уравнения: 1) (5-y)^2+17=(y-3)^2 2)7x+x(x-7)=(2x+5)(5-2x)

1) ( 5 - y) + 17 = ( y - 3) ( 5 - y)( 5 - y) + 17 = ( y - 3)( y - 3) 25 - 5y - 5y + y + 17 = y - 3y - 3y + 9 y - 10y + 42 = y - 6y + 9 y - 10y - y + 6y = 9 - 42 - 4y = - 33 4y = 33 y = 33/4 y = 8,25 2) 7x + x ( x - 7) = ( 2x + 5)( 5 - 2x) 7x + x - 7x = 10x - 4x + 25 - 10x x = - 4x + 25 x + 4x - 25 = 0 5x - 25 = 0 D = b - 4ac D = 0 - 4 * 5 * ( - 25) = 0 + 500 = 500 x = 0 + √500 / 10 = 10√5 / 10 = √5 x = 0 - √ 500 / 10 = - 10√5 / 10 = - √5