2х-12х-5х-30+6х-4=(10х+5)2+11
13х-34=100х+25+11
100х-13х=25+11-34
87х=2
х=43,5
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2x + 6 (-7+4x)=10
y=-7+4x
2x-42+24x=10
-42+26x=10
26x=10+42
26x=52
x=2
y=-7+4*2=-7+8=1
-12.cos420°=-12.cos(360°+60°)=-12.cos60°=-12.0,5=-6