3(sinx-cosx)=0
sinx-sin(π/2-x)=0
2sin(x-π/4)cosπ/4=0
sin(x-π/4)=0
x-π/4=πn
x=π/4+πn
<span>3(2x+y)-26=2(1.5x-y)</span>
<span>15-(x-3y)=2x+5</span>
<span>
</span>
<span>6х+3у-26=3х-2у</span>
<span>6х+3у-3х+2у=26</span>
<span>3х+5у=26</span>
<span>
</span>
<span>15-х+3у=2х+5</span>
<span>-х-2х+3у=5-15</span>
-3х+3у=-10
Слаживаем первое и второе
8у=16
у=2
подставляем в любое уравнение
-3х+3*2=-10
-3х=-10-6
-3х=-16
х=5¹/₃
350+10x-5y-50=480
10x-5y=180
5y=10x-180 │:5
y= 2x-36
2x-36=
│∙x
2
-36x=350 │:2
-18x-175=0
D= 324-4∙(-175) = 324 + 700 = 1024