Which best describes the association between variables x and y?

Find the surface area.

denpristay [2]

Step-by-step explanation:

a rectangular prism (like this brick) has the same basic structure as a cube (like a die) : it has 6 sides.

while a die has 6 equal sides, a rectangular prism has 3 pairs of equal sides :

top and bottom

left and right

front and back

all we have to do is calculate the areas of the 6 rectangles and add them up. that's it.

your remember, the area of a rectangle is

length × width

in our case we have

top and bottom : 2.5×11.5 × 2 = 28.75×2 = 57.5 in²

left and right : 2.5×5 × 2 = 12.5×2 = 25 in²

front and back : 11.5×5 × 2 = 57.5×2 = 115 in²

so, the total surface area of the whole block is

57.5 + 25 + 115 = 197.5 in²

5 0

1 year ago

It costs $6 to take 1 dog to the beach. It costs $1 more for each additional dog. Which is the equation, when x=1?

Leni [432]

6+1x= 7 ::::::::::::::::::::::::::::::::::

6 0

3 years ago

Not sure what to do here can someone please help

kumpel [21]

Answer:

x = 2

Step-by-step explanation:

These equations are solved easily using a graphing calculator. The attachment shows the one solution is x=2.

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<h3>Squaring</h3>

The usual way to solve these algebraically is to isolate radicals and square the equation until the radicals go away. Then solve the resulting polynomial. Here, that results in a quadratic with two solutions. One of those is extraneous, as is often the case when this solution method is used.

$\sqrt{x+2}+1=\sqrt{3x+3}\qquad\text{given}\\\\(x+2)+2\sqrt{x+2}+1=3x+3\qquad\text{square both sides}\\\\2\sqrt{x+2}=(3x+3)-(x+3)=2x\qquad\text{isolate the root term}\\\\x+2=x^2\qquad\text{divide by 2, square both sides}\\\\x^2-x-2=0\qquad\text{write in standard form}\\\\(x-2)(x+1)=0\qquad\text{factor}$

The solutions to this equation are the values of x that make the factors zero: x=2 and x=-1. When we check these in the original equation, we find that x=-1 does not work. It is an extraneous solution.

x = -1: √(-1+2) +1 = √(3(-1)+3) ⇒ 1+1 = 0 . . . . not true

x = 2: √(2+2) +1 = √(3(2) +3) ⇒ 2 +1 = 3 . . . . true . . . x = 2 is the solution

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<h3>Substitution</h3>

Another way to solve this is using substitution for one of the radicals. We choose ...

$u=\sqrt{x+2}\qquad\text{requires $u\ge0$}\\\\u^2-2=x\qquad\text{solve for x}\\\\u+1=\sqrt{3(u^2-2)+3}\qquad\text{substitute for x in the original equation}\\\\(u+1)^2=3u^2-3\qquad\text{square both sides, simplify a little}\\\\2u^2-2u-4=0\qquad\text{subtract $(u+1)^2$}\\\\2(u-2)(u+1)=0\qquad\text{factor}$

Solutions to this equation are ...

u = 2, u = -1 . . . . . . the above restriction on u mean u=-1 is not a solution

The value of x is ...

x = u² -2 = 2² -2

x = 2 . . . . the solution to the equation

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<em>Additional comment</em>

Using substitution may be a little more work, as you have to solve for x in terms of the substituted variable. It still requires two squarings: one to find the value of x in terms of u, and another to eliminate the remaining radical. The advantage seems to be that the extraneous solution is made more obvious by the restriction on the value of u.

6 0

1 year ago

Rachel set up a display placing 126 painted rocks in each of 3 rows. How many rocks arer in Rachels display? Choose numbers from

Sophie [7]

348 rocks because if you add 126 three times, or multiply it by 3, it equals 348. The numbers from the box you would use are 300, 30, and 18 then add them together

3 0

2 years ago

A rectangle has a length of 19 in and a height of 11 in. Another rectangle has a length of 95

scoundrel [369]

Answer:

Option D. No,they are not similar because their side lengths are not proportional.

Step-by-step explanation:

we know that

If two figures are similar, then the ratio of its corresponding sides is proportional and its corresponding angles are congruent

In this problem If the rectangles are similar

then

The ratio of its corresponding lengths must be equal to the ratio of its corresponding heights

<u><em>Verify</em></u>

$\frac{95}{19}=\frac{6.5}{11}\\\\95*11=19*6.5\\\\1,045\neq123.5$

therefore

The rectangles are not similar because their side lengths are not proportional.

4 0

3 years ago