{2x+3y=-7{x-y=4 => x=y+42(y+4)+3y=-72y+8+3y=-75y=-15y=-3x=-3+4=1Ответ: (1;-3)
y-x^2=0 y=x^2 y=x^2
2x-y+3=0 2x-x^2+3=0
<span>-</span><span>x</span>2<span> + </span><span>2</span><span>x + </span><span>3</span><span> = </span><span>0</span><span>D</span><span> = b</span>2<span> - 4ac = 2</span>2<span> - 4∙(-1)∙3 = 16</span><span>D</span><span> > 0 ⇒ уравнение имеет 2 корня</span><span>x</span><span> = -b ± √D / 2a</span><span>x1</span><span> = (-2 - √16) / (2∙-1) = 3</span><span>x2</span><span> = (-2 + √16) / (2∙-1) = -1 </span>
Ответ: x=-1 x=3
y=1 y=9