Question

What is the best first step to solve the system using elimination?

x – 5y = 4
3x + 7y = –17

multiply the first equation by –3

multiply the second equation by 3

solve for x in the first equation

solve for y in the second equation

Answer 1

First of all you need to multiply the two y numbers so they can be the same like multiplying the first equation by 7 to get 7x-35y=28 and the second equation multiply it by 5 to get 15x+35y=-85. there you can cancel the y's to solve for x then substitute x for your answer to get y

Answer 2

If those are your choises, then
A; will give you
1: -3x + 15y = 12
2: 3x + 7y = -17

Now you can add the 2 and eliminate x, what you have is y = ....
Then next step is to solve for x by replacing y with the value you just found