Question 69673
{{{+x-7=7}}} x-7 is in square sign
{{{sqrt(x-7)=7}}}
{{{(sqrt(x-7))^2=7^2}}}
{{{x-7=49}}}
{{{x-7+7=49+7}}}
{{{highlight(x=56)}}}
With these type of equations, always check the solutions because you can do everything right and get an extraneous solution (false).
{{{sqrt(56-7)=7}}}
{{{sqrt(49)=7}}}
{{{7=7}}} It works, x=56 is a valid solution.
Happy Calculating!!!