18) Value of b is : 
Option A is correct.
19) Option C is correct.
Step-by-step explanation:
18) We need to find the value of b.
The given equation is:

Solving to find the value of b:

So value of b is : 
Option A is correct.
19) We need to find the correct graph of the equation:

Solving:

The values of y will be less than three. As y < 3 so, the circle on y is not filled.
So. Option C is correct.
Keywords: Solving Inequalities
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It's C. it does not ship because 480 is more than 2.57 deviations from 500
Question four should be -7, question five should be 99, and question six should be 56.
-4 isn't a real number because there is no square root of -4. However, there is a cube root of -8, because -2 * -2 * -2 = -8.
The angle of depression is
tan^-1 3/7 = 23.2 deg