Question

(b²-1)(b²+1)-(b²+2)² если b=-3​

Answer 1

Ответ:

$(b²-1)(b²+1)-(b²+2)² = {b}^{2} - {1}^{2} - {b}^{4} - 4 - 4 {b}^{2} = - 5 - 4 {b}^{2} \\ - 5 - 4 \times ( { - 3)}^{2} = - 5 - 4 \times 9 = - 5 - 36 = - 41$

Answer 2

To calculate the expression $(b^2-1)(b^2+1)-(b^2+2)^2$ when $b = -3$, we substitute $b$ with $-3$ in the expression and simplify:

$(-3^2-1)(-3^2+1)-(-3^2+2)^2$

First, let's solve the expressions inside the parentheses:

$(-3^2-1) = (9-1) = 8$
$(-3^2+1) = (9+1) = 10$
$(-3^2+2)^2 = (9+2)^2 = 11^2 = 121$

Now, we substitute these values back into the original expression:

$8 \cdot 10 - 121$

Multiplying $8$ and $10$, we get:

$80 - 121$

Finally, subtracting $121$ from $80$, we have:

$-41$

Therefore, when $b = -3$, the value of $(b^2-1)(b^2+1)-(b^2+2)^2$ is $-41$.