What is the first step in solving the equation 4.2 y minus 5.2 = 18.5?

A race car is traveling at a rate of 100 yards per second.

Kobotan [32]

Answer:

204.55

Step-by-step explanation:

1 mile per hour is 0.489 yards per second

7 0

2 years ago

IF THE TRIANGLES IN THE ABOVE FIGURE ARE PROPORTIONAL, WHATS THE LENGTH OF SIDE B?

Tema [17]

<h3>Answer: choice B) 36</h3>

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Explanation:

The vertical sides, when read from left to right, can be divided to get this fraction: 9/90

Following the same order and direction, we divide the slanting corresponding sides to get: b/360

The fractions we constructed are equal to one another, as the triangles are said to be proportional.

We have the fraction 9/90 = b/360

Lets cross multiply and solve for b

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9/90 = b/360

9*360 = 90*b

3240 = 90b

90b = 3240

90b/90 = 3240/90

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A quick way to do this may be to notice how the jump from 9 to 90 is "times 10" so the jump from b to 360 is also "times 10". Think in reverse to divide 360 over 10 and we land on 36 as our answer. This line of thinking does not work as simple for all proportional problems.

5 0

2 years ago

Solve the inequality 12(1/2x-1/3)>8-2x

gizmo_the_mogwai [7]

Answer:8(1/2x - 1/4)> 12 - 2x

a.x > 7

b.x > 7/3

c.x > 5/3

d.x > 5/3

Step-by-step explanation: Solve the inequality 12(1/2x-1/3)>8-2x

3 0

2 years ago

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:

a)

Highest (-3,-3)

Lowest (2,2)

b)

Farthest (-3,-3)

Closest (2,2)

Step-by-step explanation:

To solve this problem we will be using Lagrange multipliers.

a)

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

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

b)

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

2 years ago

Whenever 2 line or intersect at 90 the 2 lines are said to be ?

Sedaia [141]

Two lines that intersect at 90 degrees are considered perpendicular to each other.

7 0

2 years ago

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