please help :( I will give you a shiny medal :D 2x-3[2x-(3-4x)] = ?? I need to simplify but I seem be getting a wrong answer. please give me detailed instructions, I would like to learn. Thank you :)

Question

please help :( I will give you a shiny medal :D  2x-3[2x-(3-4x)] = ?? I need to simplify but I seem be getting a wrong answer. please give me detailed instructions, I would like to learn. Thank you :)

kropot72 · Answer

The first step is to remove the inner brackets.
2x[2x - (3 - 4x)]=2x(2x -3 + 4x)
Next simplify the expression inside the brackets, giving
2x(6x - 3)
Now multiply out the brackets. Can you do that?

lacris · Answer

so it's 12x^2 - 6x? But I dont understand why we can remove the inner brackets? I thought we had to follow the rules and multiply everything out in the brackets first? :o

lacris · Answer

@kropot72 hello? :o

kropot72 · Answer

In cases where there are bracketed expressions within other bracketed expressions, you need to remove the innermost brackets first. In this case the inner brackets were removed by multiplying each term inside the brackets by -1:
-(3-4x) = -3 + 4x

lacris · Answer

ahh I see -(3-4x) was actually, -1(3-4x) ahh I see that

kropot72 · Answer

Good to see that you can follow :)

lacris · Answer

so the answer is just 12x^2 - 6x then? Because the answer choices have: 8x-9 , -8x +3, 9-16x, and 12x^2-24x+9. Did I do something wrong?

lacris · Answer

@jhonyy9 can you help me? :D

kropot72 · Answer

None of the answer choices that you posted relate to your question. You need to check everything.

lacris · Answer

@agent0smith I'm not sure if I'm doing this correctly

lacris · Answer

I keep getting 12x-9 for the answer..

lacris · Answer

is it the A^2+B^2 = (A+B)(A-B) law a part of this?

agent0smith · Answer

2x[2x-(3-4x)] = 12x^2 - 6x 

So either you wrote it wrong, or something. Screenshot the question maybe.

lacris · Answer

oh my gosh, I didn't even recognize that my keyboard didn't register the 2x-3 [ 2x-(3-4x)] .. I feel bad for giving the kropot a headache

lacris · Answer

oops.. but along the steps I do get 12x-18x-6x+9 when I try to simplify it and end up with 12x+9 :/ I'm not sure which part I'm simplifying wrong

lacris · Answer

yeah I will just open a new question.

agent0smith · Answer

Yeah just start another. Make sure the original problem is very clear.

lacris · Answer

yeah, it was my bad, oopsies D: