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2 years ago

A model car is 7.5 inches long made with a scale of 2 inches = 48 inches. How long is the actual car?

Mathematics

1 answer:

slava [35]2 years ago

3 0

Answer:

360

Step-by-step explanation:

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Solve 2x+3y=2 5x-y=-29 By elimination

Andreyy89

Answer:

$\huge\boxed{x=-5,\ y=4\to(-5,\ 4)}$

Step-by-step explanation:

$\left\{\begin{array}{ccc}2x+3y=2\\5x-y=-29&\text{multiply both sides by 3}\end{array}\right\\\\\underline{+\left\{\begin{array}{ccc}2x+3y=2\\15x-3y=-87\end{array}\right}\qquad\text{add both sides of the equations}\\.\qquad17x=-85\qquad\text{divide both sides by 17}\\.\qquad\dfrac{17x}{17}=\dfrac{-85}{17}\\.\qquad\boxed{x=-5}\\\\\text{Substitute it to the second equation:}\\\\5(-5)-y=-29\\\\-25-y=-29\qquad\text{add 25 to both sides}\\\\-25+25-y=-29+25\\\\-y=-4\qquad\text{change the signs}\\\\\boxed{y=4}$

5 0

3 years ago

Can you help me please ?

rusak2 [61]

Answer:

C. :)

Hope it helps

Step-by-step explanation:

8 0

3 years ago

4) Find the sum of 6\12 and 1\2 .A) 3\12 B) 9\12 C) 12\12 D) 13\12

Darina [25.2K]

Answer:

12/12

Step-by-step explanation:

6/12= 1/2

so 1/2+1/2 = One Whole and that the same thing as 12/12

5 0

3 years ago

Read 2 more answers

The plane x + y + z = 12 intersects paraboloid z = x^2 + y^2 in an ellipse.(a) Find the highest and the lowest points on the ell

emmasim [6.3K]

Answer:

Highest (-3,-3)

Lowest (2,2)

Farthest (-3,-3)

Closest (2,2)

Step-by-step explanation:

To solve this problem we will be using Lagrange multipliers.

Let us find out first the restriction, which is the projection of the intersection on the XY-plane.

From x+y+z=12 we get z=12-x-y and replace this in the equation of the paraboloid:

$\bf 12-x-y=x^2+y^2\Rightarrow x^2+y^2+x+y=12$

completing the squares:

$\bf x^2+y^2+x+y=12\Rightarrow (x+1/2)^2-1/4+(y+1/2)^2-1/4=12\Rightarrow\\\\\Rightarrow (x+1/2)^2+(y+1/2)^2=12+1/2\Rightarrow (x+1/2)^2+(y+1/2)^2=25/2$

and we want the maximum and minimum of the paraboloid when (x,y) varies on the circumference we just found. That is, we want the maximum and minimum of

$\bf f(x,y)=x^2+y^2$

subject to the constraint

$\bf g(x,y)=(x+1/2)^2+(y+1/2)^2-25/2=0$

Now we have

$\bf \nabla f=(\displaystyle\frac{\partial f}{\partial x},\displaystyle\frac{\partial f}{\partial y})=(2x,2y)\\\\\nabla g=(\displaystyle\frac{\partial g}{\partial x},\displaystyle\frac{\partial g}{\partial y})=(2x+1,2y+1)$

Let $\bf \lambda$ be the Lagrange multiplier.

The maximum and minimum must occur at points where

$\bf \nabla f=\lambda\nabla g$

that is,

$\bf (2x,2y)=\lambda(2x+1,2y+1)\Rightarrow 2x=\lambda (2x+1)\;,2y=\lambda (2y+1)$

we can assume (x,y)≠ (-1/2, -1/2) since that point is not in the restriction, so

$\bf \lambda=\displaystyle\frac{2x}{(2x+1)} \;,\lambda=\displaystyle\frac{2y}{(2y+1)}\Rightarrow \displaystyle\frac{2x}{(2x+1)}=\displaystyle\frac{2y}{(2y+1)}\Rightarrow\\\\\Rightarrow 2x(2y+1)=2y(2x+1)\Rightarrow 4xy+2x=4xy+2y\Rightarrow\\\\\Rightarrow x=y$

Replacing in the constraint

$\bf (x+1/2)^2+(x+1/2)^2-25/2=0\Rightarrow (x+1/2)^2=25/4\Rightarrow\\\\\Rightarrow |x+1/2|=5/2$

from this we get

x=-1/2 + 5/2 = 2 or x = -1/2 - 5/2 = -3

and the candidates for maximum and minimum are (2,2) and (-3,-3).

Replacing these values in f, we see that

f(-3,-3) = 9+9 = 18 is the maximum and

f(2,2) = 4+4 = 8 is the minimum

Since the square of the distance from any given point (x,y) on the paraboloid to (0,0) is f(x,y) itself, the maximum and minimum of the distance are reached at the points we just found.

We have then,

(-3,-3) is the farthest from the origin

(2,2) is the closest to the origin.

3 0

3 years ago

Convert: 100 yards to meters. A)9.14 B)91.4 C)914 D)9140

astra-53 [7]

The answer is B. 91.44

3 0

3 years ago

Read 2 more answers