A)x^2+x=0 x(x+1)=0 x=0 или x+1=0 x=-1
б)x^2-4x+3=0 D=(-4)^2-4*1*3=16-12=4 x1=(4+2)/2=6/2=3
x2=(4-2)/2=2/2=1
в) 5x^2+14x-3=0 D=14^2-4*5*(-3)=196+60=256=16^2
x1=(-14+16)/(2*5)=2/10=0,2 x2=(-14-16)/(2*5)=-30/10=-3
г)x^2-2x-2=0 D=(-2)^2-4*1*(-2)=4+8=12
x1=(2-
)/2=(2-
)/2=(2-2
)/2=(2*(1-
))/2=1-
x2=(2+
)/2=(2+
)/2=(2+2
)/2=(2*(1+
))/2=1+
д)5x=3x^2 5x-3x^2=0 x(5-3x) x=0 или 5-3x=0 -3x=-5 x=5/3=1(2/3)
е)x^2-5x+4=0 D=(-5)^2-4*1*4=25-16=9 x1=(5+3)/2=8/2=4
x2=(5-3)/2=2/2=1
ж) 7x^2-4=0 7x^2=4 x^2=4/7 x=
з) 3x^2-x+2=0 D=(-1)^2-4*3*2=1-24=-23 - корней нет
<span>-х² + 4х + 3 = 0
D = 4² + 4 · (-1) · 3 = 16 - 12 = 4
</span>
100б+100к+100с=150б+150к+50с
50с-50к=50и
с-к=б
150б+150к+50с=200б+50к+60с
100к-10с=50б
2к-0.2с=б=с-к
1.2с=3к
с=30/12к=2.5к
<u>Используем формулы упрощённого умножения. </u>
<em> Разность квадратов:</em>
<em>Сумма кубов :</em>
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