A student is trying to solve the system of two equations given below:

Equation P: x + y = 8
Equation Q: 2x + 5y = 24

Which of the following steps can be used to eliminate the x term?

2(x + y = 8)
−2(x + y = 8)
−1(2x + 5y = 24)
−2(2x + 5y = 24)

Question

A student is trying to solve the system of two equations given below: 

Equation P: x + y = 8 
Equation Q: 2x + 5y = 24 

Which of the following steps can be used to eliminate the x term?

 2(x + y = 8)
 −2(x + y = 8)
 −1(2x + 5y = 24)
 −2(2x + 5y = 24)

pumpkin1102 · Answer

it's not A

mehek14 · Answer

If it's not A, there's only 1 other option that can work

anonymous · Answer

the answer is B....the others are eliminated by substitution.

pumpkin1102 · Answer

why

mehek14 · Answer

the other equation doesn't need to be multiplied by anything

you need to multiply the first one to eliminate x

pumpkin1102 · Answer

?

anonymous · Answer

The others will cancel out both x and Y. (The correct way is substituting the value of x from the first eqn into the second. and thus eliminating x..

So..x+y=8.....x=8-y

put this into second equation
2(8-y)+5y=24

pumpkin1102 · Answer

i think that just confused me more 
gosh who invented school

phi · Answer

Equation P: x + y = 8 
Equation Q: 2x + 5y = 24 

if you want the x's  to "go away"  then you want them to add up to 0

right now you have  1 x  and another 2x's  and they add up to 3 x
Not what you want.

But look at the 2x in equation Q

phi · Answer

what do you want to do to the 2x ? you want to take away 2x
how do we takeaway 2x ?  we subtract:  2x - 2x
or   add -2x   2x+ -2x

pumpkin1102 · Answer

so you want to get rid of 2x by -2

phi · Answer

yes, the idea is to multiply by -2
which equation?  the equation that has only x, because -2 * x gives -2x
and that will add to the 2x in the other equation and give zero.

pumpkin1102 · Answer

oh I think I actually get it

anonymous · Answer

It wants us to eliminate x, and not make the equation =0

okay...second answer becomes= -2x-2y=-16
and when adding this into the second equation...x is cancelled out.and 3y=8
y=8/3

pumpkin1102 · Answer

I would medal someone but I don't know who to give it to

pumpkin1102 · Answer

help me decide who to medal I don't want to leave anyone out

pumpkin1102 · Answer

there @magicalsd

anonymous · Answer

give it to the other person...he/she might need it more...i am used to working hard

pumpkin1102 · Answer

are u sure?

anonymous · Answer

can u give to both of us?

pumpkin1102 · Answer

no the system won't let me just keep it he/she left anyways

anonymous · Answer

thanks a lot   and good luck to you.Hope you succeed.