ANSWER
Option C is the correct option
Step-by-step explanation
To find which of the expressions is equivalent. We have to expand the brackets in each of he expressions and find the answer.
We must remember that:
+ * + = +
+ * - = -
- * + = -
- * - = +
For the expression given:
-20 +(-50) + (-90)
= -20 - 50 - 90
= -160
OPTION A
-20 -(-50) - (-90)
= -20 + 50 + 90
= 120
OPTION B
-20 - (-50) + (-90)
= -20 + 50 - 90
= -60
OPTION C
-(20 + 50) + (-90)
= -20 - 50 - 90
= -160
As we can already see, Option C is the correct option.