Найдите корень уровнения

1) 7^(2-x) = 7^1
2-x = 1
x = 1

2) ОДЗ: 15-2x ≥0 2x≤15; x≤ 7.5
$\sqrt{15-2x} = 3\\ 15-2x = 9\\ 2x = 15-9\\ 2x = 6\\ x = 3$

3) 2^(2-2x) = 2^4
2-2x=4
2x=2-4
2x=-2
x=-1

4) ОДЗ: 16-2x ≥0 2x≤16; x≤ 8
$\sqrt{16-2x} = 2\\ 16-2x = 4\\ 2x = 16-4\\ 2x = 12\\ x = 6$

5) ОДЗ: 6x+57 ≥0 6x≥-57; x≥ -9,5
$\sqrt{6x+57} = 9\\ 6x+57 = 81\\ 6x = 81-57\\ 6x = 24\\ x = 4$