solve for u, u=sqrt -u+6

u=�ã-u+6

2 answers

do you mean

u = (sqrt(-6 + u))

please use the word 'sqrt' and put in ()
what is included under the radical

we will be able to assist you much faster if what you need is more clear

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u = (sqrt(-u + 6))

u = (sqrt(6 - u))
square both sides
u^2 = 6 - u
u^2 + u - 6

complete the square
u^2 + u = 6
u^2 + u + 1/4 = 6 + 1/4
(u + 1/2)^2 = 25/4
take the square root of both sides

+ - (u + 1/2) = 5/2
u + 1/2 = 5/2
u = 4/2 = 2

-u - 1/2 = 5/2
-u = 6/2 = 3
u = -3

check for u = 2
u = (sqrt(6 - u))
2 = (sqrt(6 - 2))
2 = sqrt 4
2 = 2

check for u = -3
u = (sqrt(6 - u))
-3 = (sqrt(6 + 3))
-3 = sqrt 9
-3 not = 3

so, the only solution is u = 2