1) 2x -x² = -8 ;
x² -2x -8 =0 ;
x₁=1-√(1²+8) =1 -3 =-2 ; ⇒3)
x₂ =1+√(1²+8)= 1+3 = 4,
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2)
а) 10 -7x =x+26 ;
10-26 =7x+x ;
-16 =8x;
x = -16/8 = -2.
б) 2 -3(2x+5) =(3x-15) - 6 ;
2 - 6x -15 =3x -15 -6;
2 +6 =3x+6x ;
8 =9x ;
x =8/9.