3x-8x+28=0,2x-1
-5,2x=-29
x=29÷5,2
x=290/52
x=5 30/52
x=5 15/26
<span>10(n+m)-4(2m+7n) = 10n+10m-8m-28n = 2m - 18n</span>
Д=6*6 - 4 *1*9 = 0
х = - 6/2*1
х = -3
3х²+5х-8=0
Д=25-4*3*(-8)
Д=121
х1=(-5+11)/6
х2=(-5-11)/6
х1=1
х2==-8/3=-2 2/3
1*(-2 2/3)=-2 2/3