Question 86285
sq root sign and under it is x^2 - 10x + 28 = 2. the =2 is not under the sq. root sign. 
:
{{{sqrt(x^2 - 10x + 28)}}} = 2
:
Square both sides of the equation and you have:
x^2 - 10x + 28 = 4
:
x^2 - 10x + 28 - 4 = 0; subtract 4 from both sides
:
x^2 - 10x + 24 = 0
:
Easily factored; look for two factors of 24 which add up to -10: -4 and -6
(x - 4)(x - 6) = 0 
:
x = +4
and
x = +6
:
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You can check your solutions by substituting 4 for x in the original eq:
{{{sqrt(4^2 - 10(4) + 28)}}} = 2
{{{sqrt(16 - 40 + 28)}}} = 2
{{{sqrt(4)}}} = 2
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Do the same with x = 6
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