When x varies inversely with y then you'll have
xα1/y
x=k/y where k is the proportionality constant
when x=8. y=10. k=?
8=k/10
make k the subject of the formula
k=10×8
k=80.
When x=6. y=?.k=80
6=80/y
Make y the subject of the formula
y=80/6
y=40/3
Answer:
(2,1)
Step-by-step explanation:
So the first thing you want to do is substitute. You want to plug in the equation for y in for the y value above.
So you would do 3x+4(x-1)=10. As you can see we took the bottom equation and put it in for the top equation. We did this so we only have x s and no y s.
Now you would solve. You would distribute first. You would get 3x+4x-4=10. Now combine like terms. 3+4 is 7 so you would get 7x-4=10.The next thing you want to do is get the 7x by itself so move the 4.You would get 7x=14. Now divided both sides by 7 because you want to get the x by itself.
You would get x=2. Now for the y value just plug it in for an equation above. The easier one would be y=x-1. y=(2)-1 will equal 1. You write your final answer in (x,y) style. Your final answer will then be (2,1)
You could answer this question easily by applying synthetic division:
_______________
-5 / 4 14 -9
-20 30
---------------------------
4 -6 21
R^2+r-8r-8=0
r(r+1)-8(r+1)=0
(r+1)(r-8)=0
r+1=0, r=-1
r-8=0 , r=8
answer: r=-1 or r=8