12х² + bx + 195 = 0
х₁ = - 3,75
12 * ( - 3,75)² + b* (-3,75) + 195 = 0
12 * ( - ¹⁵/₄)² - 3.75b + 195 = 0
¹²/₁ * ²²⁵/₁₆ - 3.75b + 195 = 0
⁶⁷⁵/₄ - 3.75b + 195 = 0
- 3.75b = - 195 - 168.75
- 3.75b = - 363.75
3.75b = 363.75
b = 363.75 : 3,75
b = 97
проверим:
12x² + 97x + 195 =0
D = 97 ² - 4*12 * 195 = 9409 - 9360 = 49 = 7²
x₁ = ( - 97 + 7) / (2*12) = - 90/24 = -3.75
x₂ = ( - 97 - 7) /( 2*12) = - 194/24 = - 97/12 = - 8 ¹/₁₂
Ответ: 97