Question

81 9 ----------— _ —--- 9а-а² а При а =-21

Answer 1

9*(-21)-(-21)^2*(-21)=15630

Answer 2

It looks like you have an expression with some mathematical operations and variables. Let's break it down step by step:

1. 81 - 9: This is a simple subtraction operation, which equals 72.
2. 9a: This represents the product of 9 and 'a,' where 'a' is a variable.
3. a²: This represents 'a' raised to the power of 2, which is 'a' multiplied by itself.

Now, you mentioned that this expression is evaluated when 'a' is equal to -21. Let's substitute 'a' with -21 and calculate:

1. 81 - 9 = 72
2. 9a = 9 * (-21) = -189
3. a² = (-21)² = 441

Now, let's put it all together with 'a' equal to -21:

72 - (-189) - 441

When you simplify this expression:

72 + 189 - 441 = -180

So, when 'a' is equal to -21, the expression evaluates to -180.