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Citrus2011 [14]

2 years ago

9

Solve x2 - 4x = 12 by completing the square, show work please!!

1 answer:

Rudik [331]2 years ago

8 0

$x^2-4x=12\\\\x^2-2x\cdot2=12\ \ \ |add\ 2^2\ to\ both\ sides\\\\x^2-2x\cdot2+2^2=12+2^2\ \ \ \ \ |use\ a^2-2ab+b^2=(a-b)^2\\\\(x-2)^2=12+4\\\\(x-2)^2=16\iff x-2=\pm\sqrt{16}\\\\x-2=-4\ or\ x-2=4\ \ \ |add\ 2\ to\ both\ sides\\\\\boxed{x=-2\ or\ x=6}$

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If the cost of manufacturing mobile phones is $10,000 for the factorytime plus $80 per phone and that each

ozzi

Answer:

500 phones

Step-by-step explanation:

cost of manufacturing: y = 80x + 10,000

money from phone sales: y = 100x

* note: x = #phones

solve for when they're equal;

100x = 80x + 10,000

100x - 80x = 80x - 80x + 10,000

20x = 10,000 –––––––––––> divide both sides by 20

x = 500

5 0

2 years ago

Write down the exact value of:<br> a) cos 60°<br> b) sin 0°<br> c) tan 45°

sergey [27]

Answer:

cos 60 1/2

sin0 0

tan45 1

Step-by-step explanation:

do it in calculator

7 0

2 years ago

Read 2 more answers

How do you express 0.7033?

Reika [66]

7033/10000 is the answer you're looking for

5 0

2 years ago

Subtract 10x - 7 from 2x – 6.

hichkok12 [17]

(2x - 6) - (10x - 7) # Starting expression

-8x - 1 # Combine like terms

Final answer:

-8x - 1

Hope this helps!

8 0

2 years ago

Read 2 more answers

A boat is pulled toward a dock by means of a rope wound on a drum that is located 6 ft above the bow of the boat. If the rope is

Monica [59]

Answer:

Step-by-step explanation:

Given that:

The height of the dock (h) = 6

Let represent d to be the distance between the boat and the dock

Let the length of the rope between the boat and the drum be denoted by (l)

Then, the rate of change for the length of the rope be:

dl/dt = -5 ft/s

Using Pythagoras rule to determine the relationship between these values, we have:

$l^2 = h^2 +d^2$

$l^2 = 6^2 + d^2$

$l^2 = 36 + d^2$

We relate to: $2l * \dfrac{dl}{dt} = 2d* \dfrac{dd}{dt}$

From the question;

l = 34,

So to find $\dfrac{dd}{dt}$ , we get;

$d = \sqrt{l^2 - 36}$

$d = \sqrt{34^2 - 36}$

$d = \sqrt{1156- 36}$

$d = \sqrt{1120}$

d = 33.46

So, we have:

$\dfrac{dd}{dt}= \dfrac{l}{d} \times \dfrac{dl}{dt}$

$\dfrac{dd}{dt}= \dfrac{34}{33.46} \times - 5$

$\dfrac{dd}{dt}= 1.016 \times - 5$

$\dfrac{dd}{dt}=-5.08 \ ft/sec$

4 0

2 years ago