Question

Help please on this SAT question I am practicing, Do not understand it and am freaking out

Answer 1

Post the question please. :)

Answer 2

^

Answer 3

Ill try to help if I can :3

Answer 4

@Hero get ready to work your magic

Answer 5

@Vocaloid @Hero

Answer 6

ohhhh well I should just leave I know nothing about math xD

Answer 7

You need to find the solution to the system of equations this means that you need to find the numerical value of a and the numerical value of b and then subtract b-a

Answer 8

Yes I understand that

Answer 9

(a,b) is equivalent to (x,y)

Answer 10

Yes, are you familiar with solving system of equations?

Answer 11

Yes but the (b+a) and (b-a) is confusing me in the problem

Answer 12

Don't be confused by it, solve it as you normally would, distribute the 3 to (a+b)

Answer 13

\[1.5a−4.5b=3a+3b\]
Subtract 3a from both sides:
\[1.5a−4.5b+−3a=ou get3a+3b+−3a\]
You get:
\[−1.5a−4.5b=3b\]
Add 4b to both sides:
\[−1.5a−4.5b+4.5b=3b+4.5b\]
You get:
\[−1.5a=7.5b\]
Divide both sides by -1.5:
\[\frac{ -1.5a }{ -1.5}=\frac{ 7.5b }{ -1.5a }\]

Answer 14

Ugh I dont know im ending up with a mess everytime i try it

Answer 15

Nvm, I see what pooja is leading to. Solve for a in terms of b in the first equation, then solve for b in terms of a in the first equation.

Then you'll find out the only value that a and b could be.

Answer 16

a=-5b
Sub -5b in place of a in:
\[5.5b=−2.5a+5b\]
\[5.5b=−2.5−5b+5b\]
\[5.5b=17.5b\]
Subtract -17.5b to both sides:
\[5.5b−17.5b=17.5b-17.5b\]
To get:
\[-12b=0\]
Divide both sides boy -12 to get:
\[\huge~b=0\]

Answer 17

Does this make sense?

Answer 18

I always struggle with linear equations and my SAT is coming up and I'm scared, but yeah does make sense

Answer 19

I took the SAT for times this year before getting a decent score, it's hard at first, but once you keep practicing you'll get it :) Khan academy is the way to go for practice! You're on the right path.
To complete the problem, we had said that a=-5b
We had gotten b=0 from the work previously done so :
\[\huge~a=-5(0)=0\]
So a=0 and b=0, what would our final answer be?

Answer 20

*4 times

Answer 21

pooja is doing well so far, I am just trying to think of a way to do this without as much arithmetic or distribution

Answer 22

^I was hoping there would be a shortcut of some sort because this was the SAT, you wouldn't have this much time to do this much work on the actual test

Answer 23

If you guys figure out a shortcut please share :S

Answer 24

Also a tip for the SAT, in my 4 times taking the test I have realized that the numbers are usually small when it comes to the free response math portion. This does not mean that the answer can't be big but typically it is small. This problem is a perfect example because the answer would be 0 (sorry for the giveaway) . As you can see the answer is a small number

Answer 25

Yes, that is true ... If there are any other tips anybody has about the SAT PLEASE PLEASE SHARE!

Answer 26

Also, consider looking at this
https://questioncove.com/study#/updates/59f6639f7103626820a59c00
From @Vocaloid

Answer 27

You looked at it lol *face palm* I'll pass on more things that I can think of

Answer 28

pretty sure this will be on the calculator portion of the test especially with these decimals..
after distribution you can use your calculator to find a and b values

Answer 29

Yes @pooja195 I looked at that and @Vocaloid gave me many valuable tips which I am following now, I got the khan academy idea from her, otherwise I did not know how to start

Answer 30

if you re-arrange the equations so they're in the same format you get

1.5a - 4.5b = 3(a+b)
-2.5a + 5.5b = 5(b-a)

Answer 31

@Nnesha On khan academy the question is shown as a free response

Answer 32

adding them together you get

- a + b = b - a = 3(a+b) + 5(b-a)

Answer 33

OKau and the 1.5 , -2.5 etc are ignored

Answer 34

you don't "ignore" them, it's just that the decimals cancel out and give you b - a on the left side

Answer 35

anyway, if I did my math correctly I get a = 7b and you could substitute this back into the original equation and solve for b I guess? :S

Answer 36

using this logic I also get b = 0 and a = 0

Answer 37

@pooja195

Answer 38

I got something completely different but I am very sure I am wrong

Answer 39

so I just picked one of the original equations and let a = 7b and solved for b

Answer 40

And how did you get a=7b again

Answer 41

\(\color{#0cbb34}{\text{Originally Posted by}}\) @Vocaloid
adding them together you get

- a + b = b - a = 3(a+b) + 5(b-a)
\(\color{#0cbb34}{\text{End of Quote}}\)

comes from this

Answer 42

Don't know why that link was messing up c;

Answer 43

OKay will make notes :S

Answer 44

I took that and then solved for a in terms of b

Answer 45

by expanding everything and putting a and b on separate sides of the equation

Answer 46

ANd then the other numbers canceled out right

Answer 47

we were basically left with the variables

Answer 48

\(\color{#0cbb34}{\text{Originally Posted by}}\) @Vocaloid
if you re-arrange the equations so they're in the same format you get

1.5a - 4.5b = 3(a+b)
-2.5a + 5.5b = 5(b-a)
\(\color{#0cbb34}{\text{End of Quote}}\)
I would recommend starting from here

Answer 49

okay thanks

Answer 50

add the two equations together

Answer 51

and that is what makes them cancel out then we are left with

- a + b = b - a = 3(a+b) + 5(b-a)

Answer 52

yes

Answer 53

then you distribute everything and solve for a in terms of b

Answer 54

right

Answer 55

I need help with one more type of problem let me repost it if you don't mind