All categories

3 years ago

The value of y varies directly with x, and y=3 when x=9 find y when x = 21

Mathematics

1 answer:

tester [92]3 years ago

3 0

Answer: y = 7

Step-by-step explanation:

Step 1) plug in 3 for y and 9 for x in the direct variation formula, which is y = kx

3 = k(9)

Step 2) Solve for k

3 = k(9) (Divide by 9 on both sides)

3/9 = k (Now simplify 3/9)

1/3 = k. So k = 1/3

*just FYI: “k” is the constant of variation.

Step 3) use the equation y = kx and plug in 1/3 for k

y = 1/3x

Step 4) using the equation y = 1/3x, plug in 21 for x.

y = 1/3(21) (1/3*21 is the same as 21/3)

y = 21/3 (21/3 = 7)

y = 7. So that’s you’re answer! When x=21, y=7 because 7 is 1/3 of 21!

Hope this helps! My best wishes to you as you go through school!

You might be interested in

Find x helpppppppppppp

lidiya [134]

$|2x - 1| = | - x - 2|$

Thus ;

$2x - 1 = - x - 2$

Add both sides x

$2x + x - 1 = - x + x - 2$

$3x - 1 = - 2$

Add both sides 1

$3x - 1 + 1 = - 2 + 1$

$3x = - 1$

Divide both sides by 3

$\frac{3x}{3} = \frac{ - 1}{3} \\$

$x = - \frac{1}{3} \\$

$2x - 1 = - ( - x - 2)$

$2x - 1 = x + 2$

Subtract both sides x

$2x - x - 1 = x - x + 2$

$x - 1 = 2$

Add both sides 1

$x - 1 + 1 = 2 + 1$

$x = 3$

There u go ...

3 0

2 years ago

Find the equation of the line through point (−5,5) and perpendicular to y=59x−4

VARVARA [1.3K]

Answer:

Step-by-step explanation:

5 0

1 year ago

W=zr-2zt^3 solve for z

ladessa [460]

Answer: z=0

Step-by-step explanation:

W=zr-2zt^3

Move all terms containing z to the left, all other terms to the right.

dd '-1rz' to each side of the equation.

-1rz+z=rz+-1rz+-2t^3z

Combine like terms: rz + -1rz = 0

-1rz+z=0+(-2t^3z)

-1rz+z=-2t^3z

Add 2t^3z to each side

-1rz+2t^3z+z=-2t^3z+2t^3z

Combine the like terms 2t^3z+2t^3z=0

-1rz+2t^3z+z=0

Factor out the Greatest Common Factor (GCF), 'z'.

z(-1r+2t^3+1)=0

Hope this helps, HAVE A BLESSED AND WONDERFUL DAY! As well as a great Superbowl Weekend! :-)

- Cutiepatutie ☺❀❤

8 0

3 years ago

Describe a pattern you notice when adding the sums of fractions with even denominators as opposed to those with odd denominators

GuDViN [60]

When adding fractions with even denominators, you will not get a whole number, there will be a 1/2. When adding fractions with odd denominators there will be a whole number.

8 0

3 years ago

Read 2 more answers

How much chocolate will each person get if 3 people share 1/2 lb of chocolate equally

Over [174]

1/2 / 3 = 1/2 x 1/3 = 1/6

each person will get 1/6 lb of chocolate

5 0

3 years ago

Read 2 more answers