<PRE><B>Question 506680</B>
Please help solve this equation: the square root of x squared plus 7 minus x equals 7.
Thanks!


{{{sqrt(x^2 + 7) - x = 7}}}


{{{sqrt(x^2 + 7) = x + 7}}} -------- Adding x to both sides of equation


{{{sqrt(x^2 + 7)^2 = (x + 7)^2}}} --------- Squaring both sides of equation


{{{x^2 + 7 = x^2 + 14x + 49}}}


{{{x^2 - x^2 - 14x = 49 - 7}}}


- 14x = 42


x = {{{42/(-14)}}}, or {{{highlight_green(-3)}}}



--------
Check
--------
{{{sqrt(x^2 + 7) - x = 7}}}


{{{sqrt((-3)^2 + 7) - (-3) = 7}}}


{{{sqrt(9 + 7) + 3 = 7}}}


{{{sqrt(16) + 3 = 7}}}


4 + 3 = 7 (TRUE)


Send comments and “thank-yous” to “D” at  MathMadEzy@aol.com</PRE>