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4 years ago

What is the answer for -4x+4y=12 3x-4y=-18

Mathematics

1 answer:

Liula [17]4 years ago

6 0

Use elimination.

-x = -6
X = 6

-4 (6) + 4y = 12
Y = 9

(X,y)

(6,9) is the solution

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How to prove this???

swat32

$\cos^3 2A + 3 \cos 2A \\
\Rightarrow \cos 2A (\cos^2 2A + 3) \\
\Rightarrow (\cos^2 A - \sin^2 A) (\cos^2 2A + 3) \\
\Rightarrow (\cos^2 A - \sin^2 A) (1 - \sin^2 2A + 3) \\
\Rightarrow (\cos^2 A - \sin^2 A) (4 - \sin^2 2A) \\
\Rightarrow (\cos^2 A - \sin^2 A) (4 - (2\sin A \cos A)(2\sin A \cos A)) \\
\Rightarrow (\cos^2 A - \sin^2 A) (4 - 4\sin^2 A \cos^2 A) \\ 
\Rightarrow 4(\cos^2 A - \sin^2 A) (1 - \sin^2 A \cos^2 A) 
$

go to right side now

$4( \cos^6 A - \sin^6 A)\\
\Rightarrow 4( \cos^3 A - \sin^3 A)(\cos^3 A + \sin^3 A)$

use $x^3 - y^3 = (x-y)(x^2 + xy + y^2)$ and $x^3 + y^3 = x^2 - xy + y^2$

$4( \cos^6 A - \sin^6 A)\\ \Rightarrow 4( \cos^3 A - \sin^3 A)(\cos^3 A + \sin^3 A) \\
\Rightarrow 4(\cos A - \sin A)(\cos^2 A + \cos A \sin A + \sin^2 A) \\
~\quad \quad\cdot ( \cos A + \sin A)(\cos^2 A - \cos A \sin A + \cos^2 A)$

so $\sin^2 A + \cos^2 A = 1$

$4( \cos^6 A - \sin^6 A)\\ \Rightarrow 4(\cos A - \sin A)(\cos^2 A + \cos A \sin A + \sin^2 A) \\ ~\quad \quad\cdot ( \cos A + \sin A)(\cos^2 A - \cos A \sin A + \cos^2 A) \\ \Rightarrow 4(\cos^2 A - \sin^2 A)(1 + \cos A \sin A )(1- \cos A \sin A ) \\ \Rightarrow 4(\cos^2 A - \sin^2 A)(1 - \cos^2 A \sin^2 A )\\ \Rightarrow 4(\cos^2 A - \sin^2 A)(1 - \sin^2 A \cos^2 A ) \\
 \Rightarrow Left hand side$

4 0

3 years ago

Identify the zero(s) of the function graphed below

k0ka [10]

Answer:

Step-by-step explanation:

The zeros are the values of x for which y=0.

The zero of this graph is x=1.

8 0

3 years ago

What is 70/6 as a mixed number

bija089 [108]

70/6 is basically saying "divide 70 by 6". So to get to a mixed numer, thats what you have to do.

70/6=11.666666...
(.666666..... is 2/3 as a fraction)

The answer is 11 2/3.

hope i helped!! :))

6 0

3 years ago

Read 2 more answers

Earth travels about 66,600 miles per hour as it revolves around the Sun. How far does Earth travel in 15 seconds?

o-na [289]

Step-by-step explanation:

Miles travelled in 1h=66600

Miles travelled in 1 sec=66600/3600

=18.5miles

Miles travelled in 15 seconds =18.5×15

=<em><u>277.5miles</u></em>

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3 years ago

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Someone please please help me with this !

Elanso [62]

Answer:

551.8 feet

Step-by-step explanation:

We are given

Adjacent = 1300 feet

Opposite = x

Angle = 23°

We solve using the trigonometric function Tangent

tan θ = Opposite/Adjacent

tan 23 = x/1300 feet

Cross Multiply

x = tan 23 × 1300 feet

x = 551.81726107 feet

Approximately = 551.8 feet

The Length of the building = 551.8 feet

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3 years ago