Question

1 < 4d +9 < 21
graph it on the number line

Answer 1

Answer: See the diagram below.

The graph consists of a closed circle at -2, an open circle at 3, and shading in between.

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Work Shown:

`1 \le 4d+9 < 21\\\\1-9 \le 4d+9-9 < 21-9\\\\-8 \le 4d < 12\\\\-8 / 4 \le 4d / 4 < 12 / 4\\\\-2 \le d < 3`

Notes:

In the 2nd step, I subtracted 9 from all sides to undo the "plus 9"

In the 4th step, I divided all sides by 4 to undo the multiplication.

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To graph this, you'll have a closed circle at -2 and an open circle at 3. The shaded region is in between. The open circle means "do not include this endpoint".

See the diagram below.