7х=4,9
Х=4,9/7
Х=0,7
Ответ:0,7
Производная = 1/ 2 √(4-4х-х²) *(-4-2х) = -2 (2+х) /2√(4-4х-х²) =
= -(2+х) / √(4-4х-х²)
<span>1) 6x^2+7xy-20y^2=6x</span>²-8xy+15xy-20y²=2x(3x-4y)+5y(3x-4y)=<span>(3x-4y)(2x+5y)
2) 4x</span>²-2x-1=4*(x-(1+√5)/4)(x-(1-√5)/4)<span>
D=4+16=20=4*5
x</span>₁=(2+2*√5)/8=(1+√5)/4
x₂=(1-√5)/4
1.
log2(x)>4
log2(x)>4log2(2)
x>16
(16;∞)
2.
log5(x)>1,5
log5(x)>1,5log5(5)
x>5√5
(5√5;∞)