Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ -¹ ² ³ °

You are not logged in.

|
Options

bobbym
2013-06-24 00:01:30

Hi;

Okay, you are welcome.

bronxsystem
2013-06-23 23:49:19

i understand thanks ^^

bobbym
2013-06-23 23:42:13

Hi bronxsystem;

I am hoping that you can formulate the problem. That is how to translate the words into mathematical statements.

Although I am of the type that is more interested in how then why, the ability to set the problem up is equally important.

bronxsystem
2013-06-23 23:33:03

oops yeah i see what happened

161 - 7b - 5b = 5
-7 - 5b = -156
-12b = -156
b = 13

thanks for link and help all (:

bob bundy
2013-06-23 20:54:17

hi bronxsystem

Welcome to the forum.

I'll go through it line by line

a+b = 23
a = 23 - b  OK
7a - 5b = 5

7 (23 - b) - 5b = 5  OK

151 - 7b - 5b = 5  hhmmmm  I make that 161 - 7b -5b = 5

So then it should be -12b = - 156 not -7b - 5b = 156

Multiply both sides by -1

12b = 156 back on track here but would you have got this without knowing bobbym's answer?

b = 13  OK

So, some lines correct, but your mistakes sort of cancelled each other out.

If you want more practice have a look at

http://www.mathsisfun.com/algebra/syste … tions.html

There's a long explanation of the methods you can use (which you could look at or skip if you feel confident, I think) but at the bottom there's a set of questions to try.

Bob

bronxsystem
2013-06-23 20:37:51

is this the proper working?
a+b = 23
a = 23 - b
7a - 5b = 5

7 (23 - b) - 5b = 5
151 - 7b - 5b = 5
-7b - 5b = 156
12b = 156
b = 13

and second number easy but does that working make sense?

bronxsystem
2013-06-23 20:03:37

hey thanks

any chance you can break down how you solve 7a - 5b = 5 ><
my book doesn't explain it

not being lazy i was able to do the earlier ones but just hit a wall here plzzzzzzzzzz tips and tricks

bobbym
2013-06-23 19:53:14

a + b = 23

7a - 5b = 5

The first number is 10 and the second number is 13.

Welcome to the forum.

bronxsystem
2013-06-23 19:40:56

basic algebra but im having trouble with it