2а*6а^2+ b/3a = 2*0.5 * 6*0.5^2 + (-3/4) / 3*0.5 = 1 * 6*0.25 + (-3/4)*1.5 =
= 1.5 + (-3/4)*1.5 = 1.5 (1 - 3/4) = 1.5* (1/4) = 1.5*.25=0.375
нет.....................................................................
X²-7x+q=0
x₁=11
x₁+x₂=7
11+x₂=7
x₂=7-11
x₂=-4
x₁*x₂=q
q=11*(-4)=-44
4х+7у-12=0, если у=-4
4х+7*(-4)-12=0
4х-28-12=0
4х-40=0
4х=40
х=10
23х-9у+5=0, если = -2
23х-9*(-2)+5=0
23х+18+5=0
23х+23=0
23х=-23
х=-1
5х-3у-11=0, если у=3
5х-3*3-11=0
5х-9-11=0
5х-20=0
5х=20
х=4
2х+4у+9=0,если у =1
2х+4*1+9=0
2х+4+9=0
2х+13=0
2х=-13
х=-6,5