Answer:
5
Step-by-step explanation:
Percent means parts out of 100
70%=70/100=7/10
7/10 of x=28
'of' means multiply
7/10 x=28
multiply both sides by 10/7 to get rid of fraciton
x=40
the number is 40
Step 1: Factor

1. <span> Multiply 2 by -2, which is -4.</span>
2. <span>Ask: Which two numbers add up to -3 and multiply to -4?
</span>3. <span>Answer: 1 and -4
</span>4. Rewrite

as the sum of

and


Step 2: <span>Factor out common terms in the first two terms, then in the last two terms.
</span>

<span>
Step 3: </span>Factor out the common term


Step 4: Solve for

1. Ask: When will

equal zero?
2. Answer: When

or

3. <span>Solve each of the 2 equations above:
</span>

<span>
Step 5: </span>From the values of

<span>above, we have these 3 intervals to test.
x = < -1/2
-1/2 < x < 2
x > 2
Step 6: P</span><span>ick a test point for each interval
</span>For the interval

Lets pick

Then,

After simplifying, we get

, Which is false.
Drop this interval.
<span>
For this interval

Lets pick

. Then,

. After simplifying, we get

which is true. Keep this <span>interval.
For the interval </span>

Lets pick

Then,

After simplifying, we get

, Which is false. Drop this interval.
.Step 7: Therefore,

Done! :)</span>