Т1.
(в+с)^2=в^2+2вс+с^2
(1+а)^2=1+2а+а^2
т2.
1)
=6/42+3/42+42/42-2/42=49/42=
=1 7/42=1 1/6
2)
=0.75-3/2=0.75-1.5=-0.75
т3.
1)
=(а-0.9)(а+0.9)/(а-0.9)=а+0.9=
=0.19+0.9=1.09
2)
=(а+0.5)^2/(а^2-0.25)=
=(а+0.5)^2/(а-0.5)(а+0.5)=
=(а+0.5)/(а-0.5)=(1.5+0.5)(1.5-0.5)=
=2/1=2
т4.
1)
80×1.2÷100=0.96
2)
=15%÷100%×V(51-49)(51+49)×8=
=0.15×V(2×100×8)=0.15×V1600=
=0.15×40=6
т5.
1)
2х+3х=7-0.5
5х=6.5
х=6.5÷5
х=1.3
2)
х-1=8х
8х-х=-1
7х=-1
х=-1/7
т6.
1)
(х-3)(х+3)(х-2)=0
х-3=0
х1=3
х+3=0
х2=-3
х-2=0
х3=2
2)
х(х-3)=0
х1=0
х-3=0
х2=3
т12.
1)
у=2х
х+3×2х=1
7х=1
х=1/7
у=2×1/7=2/7
(1/7;2/7)
2)
х=5у
3×5у+7у=10
22у=10
у=10/22=5/11
х=5×5/11=25/11=2 3/11
(2 3/11;5/11)
неравенства:
1)
5х>7
х>7/5
х>1 2/5
2)
7х-3х<=4-2<br>4х<=2<br>х<=2/4<br>х<=1/2