2x^2-18x+36=0
Д=324-4×2×36=36
х1=18+6/4=6
х2=18-6/4=3
(0,5a-0,6b+5,5)-(-0,5a+0,4b)+(1,3b-4,5)=0,5a-0,6b+5,5+0,5a-0,4b+1,3b-4,5=a+0,3b+1
600*0,60=360*2=720
600*0,80=480
720+480+1200=2400
А-2/a*(a+1)-3/a+1
a-2-3a/a(a+1)
-2-2a/a(a+1)
-2(a+1)/a(a+1)
-2/a
А) x=
![- \frac{-6}{2} = 3](https://tex.z-dn.net/?f=-+%5Cfrac%7B-6%7D%7B2%7D+%3D+3)
y=3²-6*3+4=9-18+4=-5
(3; -5)
б) x=
![- \frac{-4}{-4} = -1](https://tex.z-dn.net/?f=-+%5Cfrac%7B-4%7D%7B-4%7D+%3D+-1)
y=-(-1)²-4*(-1)+1=-1+4+1=4
(-1;4)
в) x=
![- \frac{-12}{6} = 2](https://tex.z-dn.net/?f=-+%5Cfrac%7B-12%7D%7B6%7D+%3D+2)
y=3*2²-12*2+2=12-24+2=-10
(2;-10)