help please

To solve for x in:

.30=.15(1)-(1-.15)x

Here are some hints:

1. Can we rewrite anything? (I.E. Simplify stuff like 3+5 to 8)
2. Can we make our lives easier by multiplying both sides (and distributing to all terms) by a certain number?

Okay
.30 = .15(1) - (1 - .15)x
.30 = .15 - (1 - .15)x
.15 = -(x - .15x)
.15 = (x + .15x) can I do that with the signs?
.15 = 1.15x
.15/1.15 = x
.13 = x
Is that right?

Let's see, redtriangle gave you some really good advice. And I am really pleased that you then had a proper go at it yourself.

ohnonotmath:

Okay
.30 = .15(1) - (1 - .15)x
.30 = .15 - (1 - .15)x good but you could have done 1-0.15=0.85 at the same time and then all the rest would have been easier.
.15 = -(x - .15x)
.15 = (x + .15x) can I do that with the signs? Not quite -(x-0.15x) = -x - - 0.15x => -x + 0.15x
When you multiply a bracket by a negative number, it changes the sign of ALL the terms inside the bracket
So from here down can't be quite right.
.15 = 1.15x
.15/1.15 = x
.13 = x
Is that right?

Do you want to give it another try?
I always like to put a zero in front of decimals (if they are less than 1) so I'd write .3 as 0.3 It makes it easier to read.

0.30 = 0.15 (1) - (1 - 0.15) x
0.30 = 0.15 - (0.85)x Thanks for that
0.15 = -0.85x
0.15/-0.85 = x
-0.176 = x
?

ohnonotmath:

0.30 = 0.15 (1) - (1 - 0.15) x
0.30 = 0.15 - (0.85)x Thanks for that
0.15 = -0.85x
0.15/-0.85 = x
-0.176 = x Your answer is not exact - you have rounded it off to 3 dec places. It can be written as a recurring decimal but there would be a lot of digits recurring. If you want it exact it is better to present it as a fraction.
?

x = 0.15/-0.85
x = -15/85 A pos divided by a neg is the same as a neg divided by a pos. The negative is better on the top. I also multiplied top and bottom by 100 to get rid of the decimals
x = -3/17 I divided numerator and denominator by 5.

That looks much better, let's just check

Thanks so much Melody! You have been such a big help.