Question

5x – 10 ≤ 20?
A) (–∞, 2]
B) (–∞, 2)
C) (–∞, 6]
D) (–∞, 6)

Answer 1

(-oo, 6] I just did this on edgenuity and the "oo" is supposed to be the symbol

Answer 2

The solutions of
`5x-10\le \:20` are
`(-\infty \:,\:6]`, so C is the correct answer.

Explanation:

The expression
`5x-10\le \:20` is an inequality. An inequality is a mathematical statement that compares two expressions using an inequality sign.

The important thing about inequalities is that there can be multiple solutions.

To find all the solutions of
`5x-10\le \:20` you must:

`\mathrm{Add\:}10\mathrm{\:to\:both\:sides}\\5x-10+10\le \:20+10`

`\mathrm{Simplify}\\5x\le \:30`

`\mathrm{Divide\:both\:sides\:by\:}5\\(5x)/(5)\le (30)/(5)`

`x\le \:6`

The graph of the inequality
`x\le \:6` is shown below.

According with the graph the solutions are less than or equal to 6, using interval notation
`(-\infty \:,\:6]`.

The solutions of
`5x-10\le \:20` are
`(-\infty \:,\:6]`, so C is the correct answer.