let's say x is the number.
x = the number
(x+2)² + x² = 10
x² + 4x + 4 +x² = 10
2x² + 4x +4 = 10
-10 -10
2x² + 4x - 6 = 0
(2x+6)(x-1) = 0 Factor
Either 2x+6 = 0 or x-1 =0
2x + 6 = 0
2x = -6
x = -3
x-1 = 0
x =1
The number is either 1 or -3. Hope this helps!
