19m=57
m=57/19
m=3
)))))))))))))
Решите !!! 2х²-32=0 ,, 4х²+4х+1=0 ,, -х²+7х+8=0 ,, -х²-2х-15=0 ,, 5х²-8х-4=0 ,, 6х²-7х+1=0
Морошка123 [35]
1) 2x^2-32=0
2x^2=32 | :2
x^2=16
x1,2=+-8
2) 4x2<span> + </span>4<span>x + </span>1<span> = </span>0
D<span> = b</span>2<span> - 4ac = 4</span>2<span> - 4∙4∙1 = 0</span>
D<span> = 0 ⇒ уравнение имеет один корень</span>
x<span> = -b/2a = -4/(2∙4) = -0.5</span>
Ответ: x=-0,5
3) -x^2<span>+ </span>7<span>x + </span>8<span> = </span>0
D<span> = b</span>2<span> - 4ac = 7</span>2<span> - 4∙(-1)∙8 = 81</span>
D<span> > 0 ⇒ уравнение имеет 2 корня</span>
x<span> = -b ± √D / 2a</span>
<span>x1</span><span> = (-7 - √81) / (2∙-1) = 8</span>
<span>x2</span><span> = (-7 + √81) / (2∙-1) = -1</span>
Ответ:<span> x = </span><span>8; -1
4) </span>x2<span> - </span>2<span>x - </span>15<span> = </span>0
D<span> = b</span>2<span> - 4ac = (-2)</span>2<span> - 4∙1∙(-15) = 64</span>
D<span> > 0 ⇒ уравнение имеет 2 корня</span>
x<span> = -b ± √D / 2a</span>
<span>x1</span><span> = (2 - √64) / (2∙1) = -3</span>
<span>x2</span><span> = (2 + √64) / (2∙1) = 5</span>
Ответ:<span> x = </span><span>-3; 5
5) </span>5x2<span> - </span>8<span>x - </span>4<span> = </span>0
D<span> = b</span>2<span> - 4ac = (-8)</span>2<span> - 4∙5∙(-4) = 144</span>
D<span> > 0 ⇒ уравнение имеет 2 корня</span>
x<span> = -b ± √D / 2a</span>
<span>x1</span><span> = (8 - √144) / (2∙5) = -0.4</span>
<span>x2</span><span> = (8 + √144) / (2∙5) = 2</span>
Ответ:<span> x = </span><span>-0.4; 2
6) </span>6x2<span> - </span>7<span>x + </span>1<span> = </span>0
D<span> = b</span>2<span> - 4ac = (-7)</span>2<span> - 4∙6∙1 = 25</span>
D<span> > 0 ⇒ уравнение имеет 2 корня</span>
x<span> = -b ± √D / 2a</span>
<span>x1</span><span> = (7 - √25) / (2∙6) = 0.166666666667</span>
<span>x2</span><span> = (7 + √25) / (2∙6) = 1</span>
Ответ:<span> x = </span><span>0.2; 1</span>
Выразим из второго уравнения y=x²-1
подставим в первое x²-3(x²-1)=-5
x²-3x²=-8
-2x²=-8
x1=2 x2=-2
y=2²-1=3
..............
1 - А
2 - Д
3 - В
4 - Б
4x-3y=12 , 4.(-6)-3(-12)=-24+36=12
3x+4y=-66 , 3.(-6)+4(-12)=-18-48=-66
/x,y/=/-6,-12/ ect rešeniem cictemi dvyx uravnenij 4x-3y=12,3x+4y=-66.