Question

11. x - y = 12 and x · y = 108 are given. Find x + y.
A) +20 B) +24 C) +28 D) +30 E) +32​

Answer 1

Ответ:

-18+30=12

х=-18

у=30

Пошаговое объяснение:

x-y=12

x*y=108

x=y+12

y=12-x

$(y + 12)y = 108 \\ y {}^{2} + 12y - 108 = 0 \\ d = 12 {}^{2} + 4 \times 108 = 576 \\ x 1= \frac{ - 12 + 24}{2} = 6 \\ x2 = \frac{ - 12 - 24}{2} = - 18$

x1=6 ❌❌❌

x2=-18

6-у=12

-у=6

у=-6

-18-у=12

-у=12+18

у=-30

-18-(-30)=12