(10t-18)=2(3t+1)
10t-18=6t+2
4t=20
t=5
10.5-18=50-18=32
3.5+1=15+1=16
32=2.16
{4x-5y=1
{2х-3у=2 |*(-2)
{4x-5y=1
{-4х+6у=-4
{4x-5y=1
+
{-4х+6у=-4
у=-3
4х-5*(-3)=1
4х=1-15
х=-14/4
х=-3 1/2
(5a+7-2b)(5a+7+2b)
(2√27+√3)^2=(6√3+√3)^2=(7√3)^2=147
19-8√3=(4-√3)^2
<span>(5а-2b)(5а+2b)-4b(3а-b)+6а(2b-1)-(а-3)(2а-5)=25a²-4b² - 12ab +4b² + 12 ab - 6a - (2a²-6a - 5a +15)=
=25a²-6a-2a²+6a+5a-15=23a²+5a-15</span>