Please help, thanks.
-Tornado

Conclusion:

Step-by-step explanation:

Checking -a - 1

From the given line number, we can determine that

The value of a will be negative because it is located on the left side of the origin 0.

i.e. value of a > -2

so

-a - 1 will be positive because if we put the value a = -1.5 let say

then

-a - 1 = -(-1.5) - 1 = 1.5 -1 = 0.5

Therefore, -a-1 will be positive.

Checking -b + 2

As b > 2

putting b = 2.1        (taking the value of b slighly above than 2)

-b+2 = -2.1+2 = -0.1

Therefore, -b + 2 will be negative.

Conclusion:

add all the numbers and check the ones place.

the answer is 486. as the ones place is more than 4, the estimation will be the next 10 ie, 490