А1+2d+a1+6d+a1+13d=15
3a1+31d=15
a1+7d=5
a8=a1+7d=5
<em><span>М*(х-2)=х^3-2x^2+x-2</span></em>
А)x-y-3=0 ⇒y=x-3; k=1;m=-3;
<span>б) 2x+3y-4=0 ⇒3y=-2x+4 ⇒y=-2/3x+4/3;⇒k=-2/3;m=+4/3</span>
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Х²-19х-24=0
a=1; b=-19; c=-24
D=b²-4ac= (-19)²-4×1×(-24)= 361+96= 457
x₁=
![\frac{-b- \sqrt{D}}{2a} = \frac{-(-19)- \sqrt{457} }{2*1} = \frac{19- \sqrt{457} }{2}](https://tex.z-dn.net/?f=+%5Cfrac%7B-b-+%5Csqrt%7BD%7D%7D%7B2a%7D++%3D+%5Cfrac%7B-%28-19%29-+%5Csqrt%7B457%7D+%7D%7B2%2A1%7D+%3D+%5Cfrac%7B19-+%5Csqrt%7B457%7D+%7D%7B2%7D+)
x₂=
![\frac{-(-19)+ \sqrt{457} }{2} = \frac{19+ \sqrt{457} }{2}](https://tex.z-dn.net/?f=+%5Cfrac%7B-%28-19%29%2B+%5Csqrt%7B457%7D+%7D%7B2%7D+%3D+%5Cfrac%7B19%2B+%5Csqrt%7B457%7D+%7D%7B2%7D+)
x₁=
![\frac{19- \sqrt{457} }{2}](https://tex.z-dn.net/?f=+%5Cfrac%7B19-+%5Csqrt%7B457%7D+%7D%7B2%7D+)
; x₂=
![\frac{19+ \sqrt{457} }{2}](https://tex.z-dn.net/?f=+%5Cfrac%7B19%2B+%5Csqrt%7B457%7D+%7D%7B2%7D+)