# algebra

the value of y varies directly with x, and y= -14 when x = 1/2. find y when x = -1.

1. 👍 0
2. 👎 0
3. 👁 91
1. two ways to do this:

1.

"y varies directly with x " y = kx , where k is a constant
when x = 1/2, y = -14
-14= (1/2)k
k = -28
so y = -28x
if x = -1
y = -28(-1) = 28

2. Just use a ratio:
(1/2) / -14 = -1/y
1/2)y = 14
y = 28

notice the actual "calculation " is the same

1. 👍 0
2. 👎 0
posted by Reiny

## Similar Questions

1. ### Math

DIRECT VARIATION 1. a is directly proportional to b.If a=15,then b=9 2. m varies directly as n.If n=2/3,then m=1/4 3. T varies as the square root of L. If L=81,then T=10 4.r varies directly as the square of t. If t=16,then r=6. 5.

asked by Mark Russel on October 17, 2009
2. ### Pre-Calc

1.) Suppose that y varies directly as x. If y is 5 when x is 30, the constant of variation is 150. True Or False 2.) If w varies directly as z and w = 9 when z = -6, find w when z = 3. 3.) If y varies directly as x and y = 2 when

asked by Anna on October 2, 2014
3. ### Variation

I have few questions that I need checked please and could you help me with the last question? Write an equation that expreses the relationship. Use k as the constant of varaiation. 1. s varies directly as h -I got: s=kh 2.a varies

asked by Soly on October 8, 2007
4. ### algebra1

M varies directly with n; m=144 when n=8. What is the constant of variation k? I don't know what this mean. Could you help me out in solving this/ A statement such as "M varies directly with n" can be changed to the equation M=kn,

asked by cheryl on March 29, 2007
5. ### math

t varies directly as the square root of l. If l=81, then t=10 what is the constant proportion? 1. a is directly proportional to b. If a = 15, then b = 9 2. M varies directly as n. If n = 2/3, then m = 1/4 3. T varies as the square

asked by Anonymous on February 6, 2012
6. ### Pre-Algebra

If y varies directly with x, find the constant of variation with x = 4 and y = -24 If y varies inversely with x, find the constant of variation with x=5 and y = 10 If y varies directly with x, and y = 35 when x = 5 , find x when y

asked by Anon on June 7, 2015
7. ### Math

This is regarding direct variation. y varies directly as the square of R. If y = 128 when R = 8, find y when R = 5. Another one I cannot figure out: If x varies directly as y, and x = 32 when y = 8, find x when y = 10 Help!

asked by Mike on April 18, 2010
8. ### Math

if y varies directly with x find the constant of variation with x=4 and y=-24. -6** 4 -96 6 if y varies directly with x and y=35 when x=5 find x when y=-7 1 7 -1** -5 if y varies directly with x and y =-12 when x=6 find x when

asked by laila solis on April 11, 2019
9. ### Algebra II

1. If y varies directly as x, and y=30 when x=4, find the constant of proportionality. 2. If y varies inversely as x, and y=2 when x=10, find x when y=4. 3. If a varies jointly as b and c, and a=-10, when b=12 and c=2, find a when

asked by JaneLee on January 28, 2008
10. ### variation

Can you please check my answers? Thanxs! Write an equation that expresses the relationship. Use k as the constant of variation. 20. f varies jointly as b and the square of c. -I got: f=kbc^2 22. r varies jointly as the square of s

asked by Soly on October 9, 2007
11. ### variation

Can you please check my answers? Thanxs! Write an equation that expresses the relationship. Use k as the constant of variation. 20. f varies jointly as b and the square of c. -I got: f=kbc^2 22. r varies jointly as the square of s

asked by Soly on October 9, 2007

More Similar Questions