How do you complete this problem step by step. x=(square root)-3x+10

x^2 = -3x+10

x^2 + 3 x - 10 = 0
(x+5)(x-2) = 0
x = 2 or x = -5 but have to check because squaring both sides is cheating
sqrt a^2 = either +a or -a and one or both may not check
try x = 2
2 = sqrt (-6+10) yes, ok, x = +2 works
try x = -5
-5 = sqrt (25) = + 5 no way
so the only solution is
x = 2