Ask question

Ask question

All categories

3 years ago

10

Suppose y varies directly with x. If y = -4 when x = 8, what is the equation of direct variation?

2 answers:

tresset_1 [31]3 years ago

8 0

$\bf \qquad \qquad \textit{direct proportional variation} \\\\ \textit{\underline{y} varies directly with \underline{x}}\qquad \qquad y=kx\impliedby \begin{array}{llll} k=constant\ of\\ \qquad variation \end{array} \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ \textit{we also know that }~~ \begin{cases} y=-4\\ x=8 \end{cases}\implies -4=k(8)\implies \cfrac{-4}{8}=k\implies -\cfrac{1}{2}=k \\\\[-0.35em] ~\dotfill\\\\ ~\hfill y=-\cfrac{1}{2}x~\hfill$

____ [38]3 years ago

6 0

Answer:

k = -1/2

y= -1/2x

Step-by-step explanation:

y = kx

We know y = -4 and x=8

-4 = k*8

Divide each side by 9

-4/8 = 8k/8

-1/2 =k

y= -1/2x

You might be interested in

Given the quadratic equation <img src="https://tex.z-dn.net/?f=y%20%3D%202%28x%20-1%29%5E%7B2%7D%20%2B%208" id="TexFormula1" tit

Sunny_sXe [5.5K]

Answer:

Part 1) "a" value is $2$

Part 2) The vertex is the point $(1,8)$

Part 3) The equation of the axis of symmetry is $x=1$

Part 4) The vertex is a minimum

Part 5) The quadratic equation in standard form is $y=2x^{2}-4x+10$

Step-by-step explanation:

we know that

The equation of a vertical parabola into vertex form is equal to

$y=a(x-h)^{2}+k$

where

(h,k) is the vertex of the parabola

if a > 0 then the parabola open upward (vertex is a minimum)

if a < 0 then the parabola open downward (vertex is a maximum)

The equation of the axis of symmetry of a vertical parabola is equal to the x-coordinate of the vertex

so

$x=h$

In this problem we have

$y=2(x-1)^{2}+8$ -----> this is the equation in vertex form of a vertical parabola

The value of $a=2$

so

a>0 then the parabola open upward (vertex is a minimum)

The vertex is the point $(1,8)$

so

$(h,k)=(1,8)$

The equation of the axis of symmetry is $x=1$

The equation of a vertical parabola in standard form is equal to

$y=ax^{2}+bx+c$

Convert vertex form in standard form

$y=2(x-1)^{2}+8$

$y=2(x^{2}-2x+1)+8$

$y=2x^{2}-4x+2+8$

$y=2x^{2}-4x+10$

see the attached figure to better understand the problem

7 0

3 years ago

200z + 50 = 8000 solve this problem

kramer

Answer:

39.75

Step-by-step explanation:

First, subtract 50 from both sides

200z + 50 - 50 = 8000 - 50

200z = 7950

Then isolate the variable by dividing both sides by 200

200z/200 = 7950/200

z=39.75

8 0

3 years ago

Identify the equation in slope-intercept form for the line that contains points (3,−10) and (6,5).

BartSMP [9]

Answer:

the answer is 5... 5- (-10) and 6-3 and divide the change by 15 and 3 and you'll get 5

Step-by-step explanation:

6 0

3 years ago

Read 2 more answers

What is the TOTAL surface area?

BartSMP [9]

Answer:

SA=571.77

Step-by-step explanation:

SA==2πrh+2πr2=2·π·7·6+2·π·72≈571.76986

pls mark brainliest

8 0

3 years ago

What is 4,000,000 times 5

Nesterboy [21]

20,000,000 is the answer fren

4 0

3 years ago

Read 2 more answers