Answer:
x=√15 or x = -5 or x=3
Explanation:
Possibility one:
x=x^2+x-15
x-x^2=x^2+x-15-x^2 (subtract x^2 from both sides)
-x^2+x=x-15
-x^2+x-x=x-15-x (subtract x from both sides)
-x^2=-15
-x^2/-1=-15/-1 (divide both sides by -1)
x^2=15
square root both sides
x=√15 or x=-√15
Possibility two:
x=(-x^2+x-15)
x=-x^2-x+15 (simplify)
x-(-x^2-x+15)=-x^2-x+15-(-x^2-x+15) (subtract both sides by -x^2-x+15)
x^2+2x-15=0
(x-3)(x+5)=0 (factor left side of equation)
x-3=0 or x+5=0 (set factors equal to 0)
x=3 or x=-5