Question

What is a possible first step to eliminate a variable in the following system?
2x – 3y = –1
3x – 4y = –3

Multiply the first equation by –3 and the second equation by 2.

Multiply the first equation by 3 and the second equation by –2.

Multiply the first equation by –4 and the second equation by 3.

All of the above.

Answer 1

@satellite73 could you help me on this?

Answer 2

to eliminate a variable, it has to have the same coefficient but with different sign in each equation.

Answer 3

alright whats next?

Answer 4

u have
ax+..
bx+..
how do u turn then numbers a and b into the same?

Answer 5

i really dont know. im having trouble.

Answer 6

*the numbers

Answer 7

no i am having trouble :/

Answer 8

u have
ax+...=...
bx+...=...
if u multiply the first equation by b and the second by a.
what do u get?

Answer 9

i'm not sure what you are talking about

Answer 10

i am terrible at math

Answer 11

@satellite73 could you pleasehelp me

Answer 12

say u have
3x-4y=2
2x-6y=3
and u multiply the first equation by 2 and the second by 3. so u get
6x-8y=4
6x-18y=9
what do u do next?

Answer 13

well u change signs: say to the first equation, so u get
-6x+8y=-4
6x-18y=9
now add both equation and get
0x-10y=5
or simply -10y=5 from which y=-1/2

Answer 14

I don't think she is online anymore

Answer 15

now u know that y=-1/2 so replace this into either of your equations, say the second one:
2x-6y=3
becomes
2x-6(-1/2)=3
2x+3=3
2x=0
x=0
so the system is solved and x=0 and y=-1/2.

try and do something similar with your exercise.