√75 +√48 - √300 = √(25×3) + √(16×3) - √(100×3) =
= 5√3 +4√3 - 10√3 = √3×(5+4-10) = √3 × (-1) = - √3
19
В 8 десятках по одной пятерке, и в десятке, на 5 начинающемся ещё 11
11+8=19
15 / ( x - 11) = 11 / (x - 15)
15 * (x - 15) = 11 * ( x - 11)
15x - 225 = 11x - 121
15x - 11x = -121 + 225
4x = 104
x = 104 / 4
x = 26
((16x^2 - 1) - (6x^2 - 4x - 2)(16x^2 - 1) - (6x^2 - 4x - 2)(16x^2 - 1) )-
- (6x^2 - 4x - 2) = (16x^2 - 1)(1 - 6x^2+4x + 2- 6x^2 + 4x + 2) - (6x^2 - 4x-2)=
= (16x^2 - 1)(- 12x^2+ 8x + 5) - (6x^2 - 4x - 2) = -192x^4 + 128x^3+80x^2 +
+ 12x^2 - 8x - 5 - 6x^2 + 4x + 2 = - 192x^4+ 128x^3 + 86x^2 - 4x- 3
При x = 3,7:
- 192*187,4161 + 128*50,653 + 86*13,69 - 14,8 - 3 =
= - 35983,891 + 6483,584 + 1177,34 - 17,8 =
= - 29500,307 + 1159,54 = - 28340,767
Как-то так................