Решите систему уравнений:
{у=2х+1
{y^2-10х-11=0

$left { {{y=2x+1} atop {y^2-10x-11=0}} right. left { {{y=2x+1} atop {(2x+1)^2-10x-11=0}} right. left { {{y=2x+1} atop {4x^2+4x+1-10x-11=0}} right.$ $left { {{y=2x+1} atop {4x^2-6x-10=0}} right.$

4x²-6x-10=0
D=b²-4ac=36-4*4*(-10)=36-16*(-10)=36+160= $sqrt{196}$ =14

x₁= $frac{6+14}{8} = frac{20}{8} = 2 frac{4}{8} =2 frac{1}{2} =2,5$

x₂= $frac{6-14}{8} = - frac{8}{8} = -1$

y=2*2,5+1=6
y=2*(-1)+1=-2+1=-1

$left { {{x=2,5} atop {y=6}} right.$

$left { {{x=-1} atop {y=-1}} right.$