<span>2*3(х+1), это степень)-3х=15</span>
<span>2*3^(x+1)-3^x=15</span>
<span>2*3^x*3-3^x=15</span>
<span>6*3^x-3^x=15</span>
<span>5*3^x=15</span>
<span>3^x=3^1</span>
<span>x=1</span>
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TgA=BC/AC=5/3⇒AC=0,6BC
AC²+BC²=AB²
0,36BC²+BC²=289
1,36BC²=289
BC²=28900/136
BC=170/2√34=85/√34
AC=3/5*85/34=51/√34=51√34/34=3√34/2
cos²A=1:(1+tg²A)=1:(1+25/9)=1:34/9=9/34
sin²A=1-cos²A=1-9/34=25/34
sinA=5/√34
sinA=CH/AC⇒CH=AC*sinA=3√34/2*5/√34=15/2=7,5
3^(5x - 13) = 9
3^(5x - 13) = 3^2 ==>
5x - 13 = 2
5x = 15
x = 3