Question

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

Equation P: y + z = 6
Equation Q: 3y + 4z = 1

Which of the following is a possible step used in eliminating the y-term?

Answer 1

@ LegendarySadist

Answer 2

a. (y + z = 6) ⋅ 4
b. (3y + 4z = 1) ⋅ 4
c. (y + z = 6) ⋅ −3
d. (3y + 4z = 1) ⋅ 3

Answer 3

please help will give medal

Answer 4

you would multiply the first equation by a -3
this will give you :
-3y - 3z = -18
3y + 4z = 1
---------------
0 + z = -17
z = -17

as you can see, when added, the y terms cancel out...they are eliminated
answer is C

Answer 5

i don't understand how you did that?

Answer 6

easy

Answer 7

what do you mean easy?

Answer 8

for the first equation multiple A -3

Answer 9

what is a -3

Answer 10

1?

Answer 11

do you know what the elimination method is, have you ever done elimination previously?

Answer 12

no

Answer 13

watch this video and tell me what your learned

Answer 14

https://www.youtube.com/watch?v=tphSgpilNv8

Answer 15

when your done tell me and im ask you a question

Answer 16

Well if we want to eliminate the y-term, we need to either make the y term above it equal to it and then subtract (substitution method) or make the number above it equal to it's negative and then add (addition method).

Answer 17

So if there is an equation like x+y=-3 and x-y=1 you add through columns to find the answer

Answer 18

Let's say we have the equations
2x+y=4

4x+3y=7
If we want to get the y alone, we would mutiply the entire top by 2 and then subtract.
2(2x+y=4)→4x+2y=8
With this we would subtract the bottom equation by the top. So
4x+2y=8

−(4x+3y=7)
to get
−y=1
In this example I was eliminating the x variable with the substitution method. Understand how the process works?

Answer 19

yes thank you so much!

Answer 20

welcme i have to go so bye

Answer 21

ok bye