Answer:
b ≤ -200
( - ∞, -200]
Explanation:
We have to solve
[tex]\frac{b}{-10}\ge20[/tex]
for b.
Multiplying both sides by -10 reverses the direction of the inequality and gives
[tex]b\le20\times(-10)[/tex]
which simplifies to give
[tex]\boxed{b\le-200.}[/tex]
We plot the above on the number line.
The above plot tells us that all values of b less than or equal to -200 satisfies the inequality.
Using the interval notation, we write the interval as
[tex](-\infty,-200\rbrack[/tex]
Where parenthesis tells us that ∞ itself is not included in the interval, the bracket '[' tells us that -200 is included in the interval.
