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View Full Version : Basic algebra need proof of answer for daughter


shugtheslug
Oct 23, 2008, 01:28 PM
y=3x-7
find value of y when x=6
please show method:mad:

ZoeMarie
Oct 23, 2008, 01:44 PM
y=(3x6)-7
y=18-7
y=11

let me know if you have questions.

ZoeMarie
Oct 23, 2008, 01:51 PM
I forgot to add that when solving equations like this there's an order that you do things in...

1. Division- check if anything needs to be divided first
2. Multiplication "
3. Subtraction "
4. Addition "

One of my teachers in middle school told us to remember it "Does McDonalds Sell Cheeseburgers?" I realize Cheeseburgers doesn't start with an "A." I don't remember if she used a different word than "addition." Maybe it would be best if your daughter remembers it "Does McDonalds Sell Apple pies?" lol

KISS
Oct 23, 2008, 02:43 PM
Not exactly, but close:

Parenthesis
Then unary minus ( 8+-2 = 6 or -2^2 = 4; not -4
Exponentiation : ex: 3+2^3 = 11

Division and multiplication (whatever is easier)

Addition and subtraction (whatever is easier)

ZoeMarie
Oct 23, 2008, 02:50 PM
Good call, KISS, but in the basic algebra class I had we didn't get into the parenthesis, unary minus or exponents yet. But you're right!

ANB428
Oct 23, 2008, 03:11 PM
It is actually Parenthesis, Exponentiation, Multiply, Division, Addition and then Subtraction. PEMDAS (Please Excuse My Dear Aunt Sally) That is how they had us remember it in High School.

aaj2008
Oct 30, 2008, 08:54 AM
It is actually Parenthesis, Exponentiation, Multiply, Division, Addition and then Subtraction. PEMDAS (Please Excuse My Dear Aunt Sally) That is how they had us remember it in High School.

Yes but the multipication and division can be intercahnged... and the subtratcion and addition parts. Multiplication does not have to be done before division and additions does not have to be before subtratcion.. see what I'm saying?

hardcorepaige69
Oct 31, 2008, 03:21 PM
y=3x-7
find value of y when x=6

y=3(6)-7
y=18-7
y=11