Ax+3ay+5x+15y=x(a+5)+3y(a+5)=(a+5)(x+3y)
(y+2)^2=16
y+2=+-4
y1=-6
y2=2
3^x>11
x>log(3)11
x∈(log(3)11;≈)
<span><span>f′</span>(x)=<span><span>(<span>(5⋅x+6)</span>⋅<span>(4⋅x−12)</span>)</span>′</span>=</span><span>=<span><span>(5⋅x+6)</span>′</span>⋅<span>(4⋅x−12)</span>+<span>(5⋅x+6)</span>⋅<span><span>(4⋅x−12)</span>′</span>=</span><span>=<span><span>(5⋅x)</span>′</span>⋅<span>(4⋅x−12)</span>+<span>(5⋅x+6)</span>⋅<span><span>(4⋅x)</span>′</span>=</span><span>=5⋅<span>(4⋅x−12)</span>+<span>(5⋅x+6)</span>⋅4
Ответ: </span>f<span>(</span><span>x</span><span>)</span><span>=</span><span>5</span><span>⋅</span><span>(4⋅x−12)</span><span>+</span><span>(5⋅x+6)</span><span>⋅</span><span>4</span>
По свойству степеней
5^(4-3x+8x-2)=1/125
5^5x+2=1/(5^3)
5^5x+2=5^-3
5x+2=-3
x=-5/5
x=-1