(12a-1)/2-1= 6a-1/2 - 1=6a-1.1/2(2a+6b)/2-24ab=a+3b-24ab
121-(11-9x)2=121-22+18x=99+18x
a/2b/2-(ab-7)/2=a/b-ab/2+7/2
b/2+49-(b-7)/2=b/2+49-b/2+7/2=52.1/2
a/4-81-(a/2+9)/2=a/4-81-a/4-9/2=-85.1/2
<span>sinx+sin5x+sin9x=0</span>
<span>2sin5xcos4x+sin5x=0</span>
<span>sin5x(1+2sin4x)=0</span>
<span>sin5x=0</span>
<span>x=пк/5</span>
<span>2sin4x=-1</span>
<span>sin4x=-0,5</span>
<span>x=-п/24+пк/4</span>
Ответ:3
Объяснение:1)1/6+1/10+1/15=5/30+3/30+2/30=10/30=1/3;
2)1/6+1/10-1/15=5/30+3/30-2/30=6/30=1/5;
3)1/3:1/5·2,52=5·2,52/3=12,6/3=4,2;
4)1/2-1/3+1/4-1/5=3/4- 8/15=45/60- 32/60=13/60;
5)1/4-1/6=3/12-2/12=1/12;
6)13/60: 1/12· 7/13=(13·12·7)/(60·13)=7/5;
7)4,2:( 7/5)= 21/5· 5/7=3.
<span>3/5x =9
х=9:3/5
х=15
30\%=0,3
15*0,3=4,5
15-4,5=10,5
Ответ: б
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