A- b = 10 ab = 7 a = b +10 b( b + 10 ) = 7 b² + 10b - 7 = 0 d = 100 + 28 = 128 = 16 * 8 = ( 8√2 )² b1 = ( - 10 + 8√ 2 ) : 2 = - 5 + 4 √ 2 b2 = ( - 10 - 8 √ 2 ) : 2 = - 5 - 4 √ 2 a = b + 10 a1 = - 5 + 4 √ 2 + 10 = 5 + 4 √ 2 a2 = - 5 - 4√ 2 + 10 = 5 + 4 √ 2 ( a + b )² ( 5 + 4 √ 2 - 5 + 4 √ 2 )² = ( 8 √ 2 )² = 64 * 2 = 128 ( 5 + 4 √ 2 - 5 - 4 √ 2 ) = 0
Спасибо