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Naddika [18.5K]
2 years ago
11

Erica solved the equation -5x - 25 = 78; her work is shown below. Identify the error and were it was made

Mathematics
1 answer:
Nata [24]2 years ago
7 0

Answer:

A

Step-by-step explanation:

It's A because she subtracted a negative and that only make a bigger negative where she should have added

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5. A car wash uses 50 gallons of water every
ira [324]

Answer:

1.25 gallons per second

Step-by-step explanation:

To figure this out divide 50 by 40

I don't know how to explain this further, hope this is good enough.

- Que

7 0
3 years ago
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Person 1 writes internal operating procedures 3 times faster than Person 2. Most of the procedures took 30 minutes each to creat
ad-work [718]

Person 1 takes 3 hour 10 minutes to complete 9 procedures

<em><u>Solution:</u></em>

From given question,

Person 2 takes 30 minutes per procedure

Person 1 writes internal operating procedures 3 times faster than Person 2

So we get, Person 1 takes 3 times faster than Person 2

Person 1 takes 10 minutes per procedure

But two of the procedures for Person 1 took an hour each

So person 1 takes 60 minutes each for two of procedures ( since 1 hour = 60 minutes )

<em><u>Calculate how long it took Person 1 to complete 9 procedures:</u></em>

So for first 7 procedures person 1 would take 10 minutes per procedure and for last two procedures person 1 would take 60 minutes per procedure

time $=7$ procedures $\times \frac{10 \text { minutes }}{1 \text { procedure }}+2$ procedure $\times \frac{60 \text { minutes }}{1 \text { procedure }}$

time=70 minutes +120minutes\\\\time=190minutes

We know that,

1 hour = 60 minutes

Therefore,

190 minutes = 60 minutes + 60 minutes + 60 minutes + 10 minutes

190 minutes = 1 hour + 1 hour + 1 hour + 10 minutes = 3 hour 10 minutes

Therefore Person 1 takes 3 hour 10 minutes to complete 9 procedures

7 0
3 years ago
At what point on the paraboloid y = x2 + z2 is the tangent plane parallel to the plane 3x + 2y + 7z = 2? (if an answer does not
Nikitich [7]
If f(x, y, z) = c represent a family of surfaces for different values of the constant c. The gradient of the function f defined as \nabla f is a vector normal to the surface f(x, y, z) = c.

Given <span>the paraboloid

y = x^2 + z^2.

We can rewrite it as a scalar value function f as follows:

f(x,y,z)=x^2-y+z^2=0

The normal to the </span><span>paraboloid at any point is given by:

\nabla f= i\frac{\partial}{\partial x}(x^2-y+z^2) - j\frac{\partial}{\partial y}(x^2-y+z^2) + k\frac{\partial}{\partial z}(x^2-y+z^2) \\  \\ =2xi-j+2zk

Also, the normal to the given plane 3x + 2y + 7z = 2 is given by:

3i+2j+7k

Equating the two normal vectors, we have:
</span>
2x=3\Rightarrow x= \frac{3}{2}  \\  \\ -1=2 \\ \\ 2z=7\Rightarrow z= \frac{7}{2}

Since, -1 = 2 is not possible, therefore there exist no such point <span>on the paraboloid y = x^2 + z^2 such that the tangent plane is parallel to the plane 3x + 2y + 7z = 2</span>.
4 0
3 years ago
X, Y and Z form the vertices of a triangle. XY = 12.4m, XZ = 10.4m and YZ = 8.7m. Find the angle ∠ YXZ rounded to 1 DP.
sweet-ann [11.9K]

Answer:

43.8°

Step-by-step explanation:

Applying,

Cosine rule,

From the diagram attached,

x² = y²+z²-2yxcos∅.................... Equation 1

where ∅ = ∠YXZ

Given: x = 8.7 m, y = 10.4 m, z = 12.4 m

Substitute these values  into equation 1

8.7² = 10.4²+12.4²-[2×10.4×12.4cos∅]

75.69 = (108.16+153.76)-(257.92cos∅)

75.69 = 261.92-257.92cos∅

collect like terms

257.92cos∅ = 261.92-75.69

257.92cos∅ = 186.23

Divide both sides by the coefficient of cos∅

cos∅ = 186.23/257.92

cos∅ = 0.722

Find the cos⁻¹ of both side.

∅ = cos⁻¹(0.7220)

∅ = 43.78°

∅ = 43.8°

6 0
3 years ago
3. Find the height of a cylinder of volume 200 cm3 and radius 4 cm.
Mrrafil [7]

Answer:

h≈3.98cm this is the answer please mark me as a brainlist

7 0
2 years ago
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