Question 427847
The error in your solution is on the fourth line: When you expand {{{(-y + 12)^2}}} you should get {{{y^2 - 24y + 144}}}, not {{{y^2 - 24y + 24}}}.


From this, we get

{{{y^2 - 24y + 144 - y^2 = 24}}}

{{{-24y + 144 = 24}}}

{{{-24y = -120}}} --> y = 5, x = 7. Also, 7^2 - 5^2 = 24.