1. 2-9x^2=0
2. -15-2x^2=-11x
3. -0,36-x^2=0
4. 16x+64=-x^2
5. 13x+3x^2=-14
6. 7x^2-3x=0
7. 5=2x-x^2
8. 16+x^2=8x
9. 1-4x^2+3x=0
10. -12x+4=-9x^2
11. 10x^2-2=x

  • 1)2-9x^2=0
    9x^2=2
    x^2=2/9
    x1=sqr2/3
    x2=-sqr2/3
    2)-15-2x^2=-11x
    -2x^2+11x-15=0
    d=121-4(-2)(-15)=121-120=1
    x1=(-11-1)/2=-6
    x2=(-11+1)/2=-5
    3)-0.36-x^2=0
    (-1)x^2=0,36
    x^2=-0,36 такого быть не может.
    4) 16x+64=-x^2
    x^2+16x+64=0
    d=256-4*1*64=256-256=0
    x=-16/2=-8
    5) 13x+3x^2=-14
    3x^2+13x+14=0
    d=169-4*3*14=169-168=1
    x1=(-13-1)/6=-14/6=-7/3
    x2=(-13+1)/6=-12/6=-2
    6) 7x^2-3x=0
    x(7x-3)=0
    x1=0
    x2=7x-3=0
    x2=3/7
    7)5=2x-x^2
    x^2-2x+5=0
    d=4-4*5=4-20  d<0 корней нет
    8)16+x^2=8x
    x^2-8x+16=0
    d=64-4*16=64-64=0
    x=8/2=4
    9)1-4x^2+3x=0
    -4x^2+3x+1=0
    d=9-4*(-4)=9+16=25=5^2
    x1=(-3+5)/(-8)=-1/4
    x2=(-3-5)/(-8)=1
    10) -12x+4=-9x^2
    9x^2-12x+4=0
    d=144-4*9*4=144-144=0
    x=12/18=4/6=2/3
    11) 10x^2-2=x
    10x^2-x-2=0
    d=1-4*10*(-2)=1+80=81=9^2
    x1=(1-9)/20=-8/20=-4/10=-2/5
    x2=(1+9)/20=10/20=1/2