Question

solve by elimination, x+y=7 and 3x-2y=11. I don't know whether I'm supposed to add or subtract. show steps plz.

Answer 1

If i knew whether i add or subtract i could get it done my self but i get confused with the addition and subtraction part.

Answer 2

\(\large {
\begin{array}{llll}
x+y=7&{\color{brown}{ 2}}\implies &2x\cancel{+2y}=14\\
3x-2y=11&\implies &3x\cancel{-2y}=11
\\\hline\\
&&\square ?+\square ?=\square ?
\end{array}
}\)

Answer 3

A) x+y=7
B) 3x-2y=11


You have to look to see which unknown an be eliminated by addition or subtraction.
Neither one can be eliminated so do you know what to do next?

Answer 4

not really

Answer 5

you could, think of it as just addition
if you add a "negative number", then you're still adding, kinda

3 + 3 = 6
3 - 2 = 1 or 3 + (-2) = 1, same thing

Answer 6

where do u get the other 3? it 1x and 3x

Answer 7

hmmm that was just an example
meaning that, a subtraction could also be seen as an addition, with a negative number

Answer 8

ur confusing me

Answer 9

Hello kearsten - guess jdoe0001 left
I can take over

Answer 10

hmm
well... notice above... the elimination, we used a factor of "2"
so, "add" or "subtract" away then

Answer 11

ok

Answer 12

As I previously posted:

A) x+y=7
B) 3x-2y=11


You have to look to see which unknown an be eliminated by addition or subtraction.
Neither one can be eliminated so do you know what to do next?

Answer 13

idk, my question says to use elimination.

Answer 14

You have to eliminate the x or the y by adding or subtracting the equations.
You can see it can't be done just by addition or subtraction right?

Answer 15

ok

Answer 16

Let's look at the equations again
A) x+y=7
B) 3x-2y=11

We will have to multiply one of those by a number so that when the 2 are added or subtracted, we can eliminate the x or y

Answer 17

so times equation a by 3 or 2?

Answer 18

If you multiply equation A by 2 you'll see it produces 2y
equation B has a -2y so adding those equations will eliminate the y

Answer 19

so equation a will be 2x+2y=7? or would it be x+2y=7?

Answer 20

you have to multiply ALL of the equation by 2

Answer 21

neither of those equations you typed are correct

Answer 22

so 2x+2y=14?

Answer 23

yes !!

Answer 24

Now add it to equation B

Answer 25

x=5?

Answer 26

Let's not skip anything
2x + 2y = 14
3x-2y=11

5x = 25

x=5

Answer 27

ok i got that but simplified

Answer 28

the next step is to get the value of x=5 and put it into either equation

Answer 29

3x-2y=11
3(5)-2y=11
15-2y=11
2y=26
y=13?

Answer 30

or is it x+y=7
5+y=7
y=2?

Answer 31

Not quite
15-2y=11
4 = 2y

Y=2

Answer 32

Yes y = 2

Answer 33

awesome, i got it right! sorta. thanks for the help wolf!

Answer 34

glad to help :-)

Answer 35

??? no idea y that change spots. thnks for the help ur a life saver