Answer:
x= √10 and x= -√10
Explanation:
first look to isolate the term with the variable on one side
-5 +5 -2x² = -5 -15; subtract 5 from both sides(inverse of addition)
-2x² = -20; divide both sides by -2 (inverse of multiplication)
x² = 10; square root both sides (the inverse of raising to power of 2)
√x² =√10
x =±√10