First make sure that one of the variable has the same coefficient in each equations.
For example lets use:
y=x+3
2y=3x-1
Since neither the y's or x's are the same, we must multiply the equations to make them the same. I am going to multiply the first equation by 2 so I can eliminate the y's.
So we get:
2y=2x+3
2y=3x-1
Then we subtract the second equation from the first to eliminate the y's. So we end up with 0=-x+4 and now we solve for x
0=-x+4
x=4
Now we plug in our x into either original to get the y-value. I am using the first
y=x+3
y=4+3
So the x=4 and y=7
Hope this helps!
You would need 105 of sodium I found how much increase there was from 30 to 75 by doing 75/30 which is 2.5 that means the new amount of sodium would be 2.5 times 42 which is 105. You could also set up ratios and cross multiply like the picture I sent
<em>Answer:</em>
–6.8
<em>Method:</em>
Counting backwards from –7 to –6.5
