4х²-20х+25+25х²-30х+9-75-2х=0
29х²-50х-50=0
D=2500+29*4*50=8300
x₁=50+√8300/58=50+10√83/58=25+5√83/29
x₂=50-10√83/58=25-5√83/29
X^2-2x+x+2-x^2= -x+2
<span>7x^2-4x-24+-x^2= 6х^2-4х-24
</span>7x^2-6x-11+-x^2-2x+13= 6х^2-8х+2
2x^2-8x+13+(x-5)^2= 2x^2-8x+13+х^2-10х+25= 3х^2-18х+38
<span>(x+1)^2+(x-2)^2= х^2+2х+1+х^2-4х+4= 2х^2-2х+5
</span><span>(x-10)^2+(1-x)^2= х^2-20х+100+1-2х+х^2= 2х^2-22х+101
</span>Вот так вот
X1+x2=-1.5
x1*x2= 0.5
По теореме Виета
x^2+0.5x-1.5