Question

-2a-3/1-a^2 + 2-a/a^2-1 при а=-2

Answer 1

(-2а - 3)/(1 - а²) + (2 - а)/(а² - 1) =

= (-2а - 3)/(1 - а²) - (2 - а)/(1 - а²) =

= (-2а - 3 - 2 + а)/(1 - а²) = (-а - 5)/(1 - а²)

Answer 2

To evaluate the expression (-2a - 3)/(1 - a^2) + (2 - a)/(a^2 - 1) when a = -2, follow these steps:

Step 1: Substitute the value of "a" into the expression. Step 2: Perform the calculations.

Let's do that:

Step 1: Replace "a" with -2 in the expression:

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

Step 2: Now, simplify the expression:

(-2(-2) - 3)/(1 - 4) + (2 + 2)/(4 - 1)

Calculate the numerator first:

(-2(-2) - 3) = (4 - 3) = 1 (2 + 2) = 4

Now, calculate the denominators:

1 - 4 = -3 4 - 1 = 3

Now, we have:

1/-3 + 4/3

To add the fractions, they need to have the same denominator. So, let's find a common denominator, which is 3:

1/-3 + (4 * -1)/3

Now, we have:

-1/3

So, when a = -2, the expression evaluates to -1/3.