√x + fourth root of x = 30

x^(1/2)  +  x^(1/4)   = 30        subtract 30 from both sides

x^(1/2)   +  x^(1/4)  - 30    =  0     we can factor this directly as

[  x^(1/4 )  +  6  ]    [ x^(1/4)  - 5  ]   =  0

Settting both of these factors to 0  and solving for x, the first produces no solution

For the second, we have that

x^(1/4)  - 5  = 0     add 5 to both sides

x^(1/4)  = 5           take both sides to the 4th power

x  = 5^4   =    625