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3 years ago

Can someone help me PLZ! I keep posting the same question and no ones helping me :((((((((((((

Mathematics

1 answer:

kipiarov [429]3 years ago

3 0

Answer:

Multiply x + y = 3 by 3 and add it to -3x - 2y = -7

Step-by-step explanation:

When using elimination to solve a system of equations, you multiply one equation by some number. The reason for doing this is that when you add it to the second equation, you want one variable to cancel out. When one variable cancels out (in this case x), you can solve for the other variable (in this case y). I will show this:

3(x + y = 3) = 3x + 3y = 9

3x + 3y = 9

+ -3x + -2y = -7

---------------------------

y = 2

Now, knowing that y = 2, you can substitute y=2 into either equation to solve for x.

-3x - 2(2) = -7

-3x -4 = -7

-3x = -3

x = 1 | to double check (1, 2) as your answer plug these values into both equations

Finding this solution would not have been possible if not for cancelling out the x's above. The other three are wrong because none of the other options cancels out one of the variables.

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miguel is posting photos on a school website. He has 48 photos, and he is allowed to use 12 pages. He wants to put the same numb

Vlad1618 [11]

Answer:

4 pages

Step-by-step explanation:

48 divided by 12 = 4

8 0

2 years ago

When two equal forces are inclined at an angle 2a their resultant is twice as great as

swat32

Step-by-step answer:

Referring to the attached diagram, the resultant of two forces each with magnitude F and inclined to each other at 2a equals

Ra = 2Fcos(a) ..............................(1)

Similarly, the resultant of two forces each with magnitude F and inclined to each other at 2b equals

Rb = 2Fcos(b)..............................(2)

We are given that

Ra = 2Rb ....................................(3)

Substitute (1) & (2) in (3) gives

2Fcos(a) = 2(2Fcos(b))

Expand

2Fcos(a) = 4Fcos(b)

Simplify

cos(a) = 2 cos(b) QED

Note: Please note that you might have a faster response if you posted this question in the physics or the (new) Engineering section.

Have a nice day!

5 0

3 years ago

Is it possible for a right triangle with a leg that is 12 inches long and a hypotenuse that is 37 inches long to be congruent to

Llana [10]

9514 1404 393

Answer:

x = 35

Step-by-step explanation:

It appears the only missing piece of the explanation is ...

x² = 1225 ⇒ x = 35

7 0

3 years ago

Someone please help me!!!!

BARSIC [14]

Answer: see proof below

<u>Step-by-step explanation:</u>

Use the Double Angle Identity: cos 2A = 2cos²A - 1

Use the Difference Identity: cos (A - B) = cosA · cosB + sinA · sinB

Use the Unit Circle to evaluate: cos (π/2) = 0 & sin (π/2) = 1

<u>Proof LHS → RHS</u>

$\text{Given:}\qquad \qquad \qquad \qquad 2\cos^2\bigg(\dfrac{\pi}{4}-\dfrac{A}{2}\bigg)-1\\\\\\\text{Double Angle Identity:}\quad \cos2\bigg(\dfrac{\pi}{4}-\dfrac{A}{2}\bigg)\\\\\\\text{Simplify:}\qquad \qquad \qquad \quad \cos\bigg(\dfrac{\pi}{2}-A\bigg)\\\\\\\text{Difference Identity:}\qquad \cos\dfrac{\pi}{2}\cdot \cos A+\sin \dfrac{\pi}{2}\cdot \sin A\\\\\\\text{Unit Circle:}\qquad \qquad \qquad 0\cdot \cos A+1\cdot \sin A\\\\\\\text{Simplify:}\qquad \qquad \qquad \qquad \sin A$

LHS = RHS: sin A = sin A $\checkmark$

4 0

4 years ago

Read 2 more answers

What is the value of x 3/5x-1/3x=x-1

Stella [2.4K]

Answer:

x=15/11

x=1.36

Step-by-step explanation:

8 0

3 years ago