Найменше значення виразу 9x^2+y^2-6x+2y

Все слагаемые разделим на 15^x > 0; 25* 9^x / 15^x - 34* 15^x / 15^x + 9* 25^x / 15^x = 0; 25 * (3/5)^x - 34 * 1 + 9* (5/3)^x = 0; (3/5)^x = t  > 0;     (5/3)^x = 1/t; 25* t   - 34 + 9 / t = 0;     *t; 25t^2 - 34 t + 9 = 0; d = 34^2 - 4*25*9 = 1156 - 900 = 256= 16^2;   t1 =(34+16) / 50 = 1;   ⇒ (3/5)^x = 1;     x = 0.   t2 = (34 - 16) / 50 = 18/50 = 9/25;   ⇒ (3/5)^x = 9/25;   (3/5)^x = (3/5)^2 ; x = 2ответ: х =0 или х =2

1) xn = 1/ (2n -1). x1 = 1 / (2*1 -1) = 1/(2 - 1) =   1; x2 = 1/(2*2 -1) = 1/(4 - 1) = 1/3  ;   x3 = 1/(2*3 -1) = 1/(6 - 1) = 1/5; x4 = 1/(2*4  -1) = 1/(8 - 1) = 1/7; x5 = 1/(2*5 -1) = 1/(10 -1) = 1/9. xn   1; 1/3 1/5; 1/7; 1/9 2) xn =4n^2 + 3n + 2; x1 = 4*1^2 + 3*1 + 2 = 4+3+2 = 9; x2 = 4*2^2 + 3*2 + 2 = 16+6+2 = 24;   x3 = 4*3^2 + 3*3 + 2 = 36+9+2 = 47;   x4 = 4*4^2 + 3*4 + 2 = 64 + 12 + 2 = 78; x5 = 4* 5^2 + 3*5 + 2 = 100+15+2 = 117. xn   9,   24,  47, 78, 117