anonymous
  • anonymous
4. If x = 20 when y = -4, find y when x = 10.
Algebra
  • Stacey Warren - Expert brainly.com
Hey! We 've verified this expert answer for you, click below to unlock the details :)
SOLVED
At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus. Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.
chestercat
  • chestercat
I got my questions answered at brainly.com in under 10 minutes. Go to brainly.com now for free help!
Ahsome
  • Ahsome
Is this a linear equation, @dianolove?
Ahsome
  • Ahsome
Wait, couldn't you do: \[\begin{align} y&=kx\\ -4&=k\times20\\ k&=\dfrac{-1}{5} \end{align}\]
anonymous
  • anonymous
this is the question it asked me Suppose that x and y vary inversely. Write a function that models each inverse variation. Then use the equation to solve the problem.

Looking for something else?

Not the answer you are looking for? Search for more explanations.

More answers

anonymous
  • anonymous
Let's solve your equation step-by-step. 20x−4x=10 Step 1: Simplify both sides of the equation. 20x−4x=10 Simplify: (Show steps) 16x=10 Step 2: Divide both sides by 16. 16x16=1016 x=58 Answer: x=58
anonymous
  • anonymous
do you under stand
anonymous
  • anonymous
20x−4y=10
phi
  • phi
*** x and y vary inversely*** means you can write the formula \[ y = \frac{k}{x} \]
anonymous
  • anonymous
it is a inverse variation and your solving for y not x
phi
  • phi
that formula is useful if we know what "k" is. to find k, we use the info If x = 20 when y = -4, find y when x = 10.
phi
  • phi
in other words, replace x with 20 and y with -4 into the formula \[ -4= \frac{k}{20} \] and "solve for k" by multiplying both sides by 20
phi
  • phi
can you find what k is ?
anonymous
  • anonymous
k is -80
phi
  • phi
yes, so now you know the formula (for this problem) is \[ y = \frac{-80}{x} \] find y when x = 10. to find y, replace x with 10 in the formula and simplify
anonymous
  • anonymous
y=-8
phi
  • phi
yes
anonymous
  • anonymous
thanks phi will you keep helping me with these i got another one
phi
  • phi
ok
anonymous
  • anonymous
If x = 5 when , find y when x = 10.
phi
  • phi
missing some info
anonymous
  • anonymous
5. If x = 5 when y=-1 third , find y when x = 10.
phi
  • phi
do you mean if x=5 when y = \( - \frac{1}{3} \) ?
anonymous
  • anonymous
sorry mines will not do that but yes
anonymous
  • anonymous
is k -30
phi
  • phi
you could type it as y= -1/3 \[ y = \frac{k}{x} \\ - \frac{1}{3} = \frac{k}{5} \] to find k, multiply both sides by 5 \[ - \frac{1}{3} \cdot 5 = \frac{k}{5}\cdot 5 \\ - \frac{1}{3} \cdot 5 = k \cdot \frac{5}{5} \\ - \frac{5}{3} = k \]
anonymous
  • anonymous
-15
phi
  • phi
what is -15 ? k is -5/3
anonymous
  • anonymous
oh i thought you said t multiply -5 into 3 , but what do you do now divide -5/3 into 10
phi
  • phi
you write the formula \[ y = \frac{k}{x} \] and it might be easier to understand if you write it this way \[ y = k \cdot \frac{1}{x} \] which means the same thing. now replace k with -5/3 \[ y = - \frac{5}{3} \cdot \frac{1}{x} \]
phi
  • phi
find y when x = 10. that means put in 10 for x in the formula \[ y = - \frac{5}{3} \cdot \frac{1}{x} \\ y = - \frac{5}{3} \cdot \frac{1}{10}\] and simplify
anonymous
  • anonymous
y=6
phi
  • phi
if you use a calculator on \[ - \frac{5}{3} \cdot \frac{1}{10} \] what do you get ?
anonymous
  • anonymous
-1/6
phi
  • phi
yes, y= -1/6 when x=10. It would be good to be able to do that without the calculator. when you multiply fractions, you multiply top times top and bottom times bottom \[ - \frac{5}{3} \cdot \frac{1}{10} = - \frac{5 \cdot 1 }{3 \cdot 10} \] we could multiply the bottom 3*10 to get 30 \[ - \frac{5}{30} \] and then simplify to get -1/6 or, it's easier to notice that 10 is 2*5 \[ - \frac{5 \cdot 1 }{3 \cdot 10} = - \frac{5 \cdot 1 }{3 \cdot 2 \cdot 5} \] and notice we have a 5 up top and down below, and they simplify to 5/5 = 1 \[ - \frac{1 }{3 \cdot 2} = - \frac{1}{6} \]
anonymous
  • anonymous
what if x=-4/15 when y=-105,find x when y=4
phi
  • phi
\[ y = k \cdot \frac{1}{x} \\ -105= k \cdot \frac{1}{-\frac{4}{15}} \]
phi
  • phi
multiply both sides by -4/15,
anonymous
  • anonymous
k=28
phi
  • phi
so \[y = \frac{28}{x} \] find x when y=4 replace y with y \[ 4 = \frac{28}{x} \]
phi
  • phi
first multiply both sides by x then divide both sides by 4
anonymous
  • anonymous
7
phi
  • phi
yes. \[ 4 x= \frac{28}{x} \cdot x \\ 4x = 28 \\\frac{4x}{4}= \frac{28}{4} \\x=7\]
anonymous
  • anonymous
thanks are you getting tired of me asking questions
phi
  • phi
no, but I do have to go. make a new post and someone will help you.
anonymous
  • anonymous
ok thanks

Looking for something else?

Not the answer you are looking for? Search for more explanations.