1. 840 brushes decreased by 25%
2. $84 increased by 7%
( fully explain how to do both of these with the answer, thanx! )

Explaining? Simple!

1. In order to find the answer you simply change 25% to decimal form then multiply by your brushes. Then subtract your value from the original:

25% ⇒ .25 [Note: All percentages are less than one]

[840 x .25] = 210

[840 - 210] = 630.

840 decreased by 25% is 630.

2. For this one, you do the exact same thing as the first one, except you add since it is being increased. So convert 7% to decimal form and then multiply it by your money. The add this value to the original:

7% ⇒ .07 [*Note*: This is 7% not 70%]

[84 x .07] = 5.88

[84 + 5.88] = $89.88. (Don't forget to add your symbols!).

$84 increased by 7% is $89.88!

Where is your question?