Simple problem - Hoping simple mistake

[Artimid]

Problem: 4(8-5(-2x-4))=40x+112
So, I am ending up with 4(3(-2x-4)=40x+112
Following to 4(-6x-13)=40x+112

The problem is the answers show that it should come out to 4(10x+28)=40x+112 and I just can't seem to get how that answer is gotten, as it mutiplies the first term in the parenthesis by -5 to get 10x, and the second term by -7 to get 28.

The rest of the problem isn't an issue, and I know this is simple.. but I just seem to have a block for some odd reason on this problem. Any help would be greatly appreciated.

 

[Deleted member 4993]

Problem: 4(8-5(-2x-4))=40x+112
So, I am ending up with 4(3(-2x-4)=40x+112 <<< That is your first mistake. With multiple-levels of parentheses - you must deal with the inner parenthesis first

4 [8 - 5(-2x - 4)] = 40x + 112

4 [8 + 10x + 20] = 40x + 112

and so on....

Following to 4(-6x-13)=40x+112

The problem is the answers show that it should come out to 4(10x+28)=40x+112 and I just can't seem to get how that answer is gotten, as it mutiplies the first term in the parenthesis by -5 to get 10x, and the second term by -7 to get 28.

The rest of the problem isn't an issue, and I know this is simple.. but I just seem to have a block for some odd reason on this problem. Any help would be greatly appreciated.

 

[fasteddie65]

You violated the order of operations. PEMDAS: Parentheses, exponents, multiply and divide (from left to right), and finally add and subtract (from left to right).

Problem: 4(8 - 5(-2x - 4)) = 40x + 112
So, I am ending up with 4(3(-2x - 4) = 40x + 112

You subtracted 8 - 5 first, when you should have distributed the 5 over (-2x - 4) first instead.

 

[Artimid]

Aha, I knew it was a simple but foolish mistake. >_< I had hoped, of course, that it wasn't.. but I knew it was. This would have gotten me on a test, so I appreciate the help and the reminder about that order. I thought I was following it by making sure of the 8-5, but I didn't see it as 8-(5*(-2x-4). So thank you again.

 

[Denis]

Problem: 4(8-5(-2x-4))=40x+112
So, I am ending up with 4(3(-2x-4)=40x+112

You'd be correct IF equation had an extra set of brackets: 4([8-5](-2x-4))=40x+112