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3 years ago

Come hither big brains

Mathematics

1 answer:

katrin2010 [14]3 years ago

7 0

Answer:

The answer is c

Step-by-step explanation:

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Solve each quadratic equation by completing the square. 6. x2 + 2x = 8 7. x2 - 6x = 16 8. x2 - 18x = 19 9. x2 + 3x = 3 10. x2 +

Andrei [34K]

Lets get started :)

These questions have asked us to solve by completing the square.
How do we? I have attached a picture, which will explain

6. x² + 2x = 8
→ b is the coefficient of x, which is 2
→ We take half of 2 and square it. Then, we add it to either side

x² + 2x $+ (\frac{2}{2} )^2 = 8 + ( \frac{2}{2})^2$
x² + 2x + 1 = 8 + 1
( x + 1 )( x + 1 ) = 9
( x + 1 )² = 9
$\sqrt{( x + 1 )^2} = \sqrt{9}$
x + 1 = + 3 or x + 1 = - 3
x = 2 or x = - 4

7. x² - 6x = 16

→ We do the same thing we did in the previous question

x² - 6x + $(\frac{6}{2})^2 = 16 + (\frac{6}{2})^2$
x² - 6x + 9 = 16 + 9
(x - 3)² = 25
$\sqrt{(x-3)^2} = \sqrt{25}$
x - 3 = + 5 or x - 3 = - 5
x = 8 or x = - 2

8. x² - 18x = 19

x² - 18x + $( \frac{18}{2} )^2 = 19 + ( \frac{18}{2})^2$
x² - 18x + 81 = 19 + 81
( x - 9 )( x - 9 ) = 100
( x - 9 )² = 100
$\sqrt{(x-9)^2} = \sqrt{100}$
x - 9 = + 10 or x - 9 = -10
x = 19 or x = - 1

9. x² + 3x = 3

x² + 3x + $( \frac{3}{2} )^2 = 3 + (\frac{3}{2} )$
$x^2 + 3x + \frac{9}{4} = 3 + \frac{9}{4}$
$x^{2} + 3x + \frac{9}{4} = \frac{21}{4}$
$(x^2 + \frac{3}{2} ) ( x^2 + \frac{3}{2} ) = \frac{21}{4}$
$( x^2 + \frac{3}{2} )^2 = \frac{21}{4}$
$\sqrt{ x^2 + \frac{3}{2} } = \sqrt{ \frac{21}{4} }$
x + $\frac{3}{2}$ = + $\frac{ \sqrt{21} }{2}$ or x + $\frac{3}{2} = - \frac{ \sqrt{21} }{2}$
x = $\frac{-3+ \sqrt{21} }{2}$ or x = $\frac{-3 - \sqrt{21}}{2}$

7 0

3 years ago

Can you plz help me I don’t get it

levacccp [35]

35 feet.

$\frac{mailbox height}{mailbox shadow}$

$\frac{pinetree height}{pinetree shadow}$

$\frac{3}{4.8} = \frac{h}{56}$

1.8h = 3 x 56

4.8h = 168

h = 35 feet.

5 0

3 years ago

Read 2 more answers

What is the area of a triangle when the sides are 17, 8 and 9

sleet_krkn [62]

Answer:

ok so to solve this you need to do base x height then divide that by 2

Step-by-step explanation:

7 0

3 years ago

Choose the imensions that represen this rectlangl

almond37 [142]

Answer:B

Step-by-step explanation:I hope it help

3 0

3 years ago

Use signed numbers to solve. A helicopter descended 1200 feet, rose 800 feet, and then descended 450 feet. What was the net gain

sergey [27]

The rise or an increase in altitude is represented by positive sign and a decend or decrease in altitude is represented by negative sign.

First the helicopter descended 1200 feet. So the change in altitude will be -1200 feet.

Then the helicopter rose by 800 feet. So the change in altitude will be 800 feet.

Finally the helicopter descended by 450 feet. So the change in altitude will be -450 feet.

The net change in altitude will be the sum of all the above 3 changes.
Change in altitude = -1200 + 800 - 450 = -850 feet

The negative sign indicates a descend i.e. loss in altitude. So the net change in altitude was a loss of 850 feet.

3 0

3 years ago