16-40х+25х^2=5X-4-50X^2+40X
16-40X+25X^2=45X-4-50X^2
16-40X+25X^2-45X+4+50X^2=0
20-85X+75X^2=0
75X^2-85X+20=0 :5
15X^2-17X+4=0
D= 17^2-15*4*4=289-240=49=7
X=17-7/2*15=10/30=1/3
X=17+7/30=0,8
1. Х²+6х+9
У²-16у+64
(7-х-5+х)(7-х+5-x)=2(12-2x)=24-4x
5x(x-4)=5x²-20x
8-4x+2x-x²=-x²-2x+8
2. У=-2*7,5+3=-12
3. 2х²-20х+25+20х=2х²+25
36с-3(1+12с+36с²)=36с-3-36с-108с²=-3-108с²
9+24+q=0
q=-33
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