1.
1-7ˣ² * 49ˣ ≥0
-7ˣ² * 7²ˣ ≥ -1
7^(x²+2x)≤ 7⁰
x²+2x≤0
x(x+2)≤0
x=0 x= -2
+ - +
--------- -2 ------------- 0 ------------
\\\\\\\\\\\\\\\\
x∈[-2; 0]
D(f)=[-2; 0]
2.
(0.3*3)ˣ = (81*10⁻²)^(¹/₃)
(9*10⁻¹)ˣ = (9² * 10⁻²)^(¹/₃)
9ˣ * 10⁻ˣ = 9^(²/₃) * 10^(- ²/₃)
x= ²/₃
Ответ: ²/₃.