Final answer:
The value of the expression -3x³+6x²−5x−9 when x=−3 is 141.
Step-by-step explanation:
An expression is a combination of numbers, symbols, and operators that represents a mathematical quantity or relationship. Expressions can be simple or complex and are used to describe various mathematical relationships or computations.
To evaluate the expression -3x³+6x²−5x−9 when x=−3, we substitute -3 for x in the expression.
-3(-3)³+6(-3)²−5(-3)−9
Simplifying this expression step by step, we get:
(-3)(-27)+6(9)+15-9
81+54+15-9
141
Therefore, when x = -3, the value of the expression is 141.