16.
35√ [(x + 2)3 ] + 3 = 27 subtract 3 from both sides
35√ [(x + 2)3 ] = 24 divide both sides by 3
5√ [(x + 2)3 ] = 8 take each side to the 5/3 power
(x + 2) = 85/3 and we can write
(x + 2) = ( 81/3)5
(x + 2) = 25
x + 2 = 32 subtract 2 from both sides
x = 30
17.
√[2x + 13 ] - 5 = x add 5 to both sides
√[ 2x + 13 ] = x + 5 square both sides
2x + 13 = x^2 + 10x + 25 subtract 2x, 13 from both sides
x^2 + 8x + 12 = 0 factor
(x + 6) ( x + 2) = 0
Set each factor to 0 and solve for x and we have that
x = -6 or x = - 2
The first solution does not solve the original equation
Only the second is good