1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
snow_tiger [21]
2 years ago
13

Completing the square: x^2+2x-7=8x

Mathematics
1 answer:
tia_tia [17]2 years ago
4 0

Answer: x = 7, x = -1

Step-by-step explanation: Move the term to the left side

x^2 + 2x - 7 = 8x

x^2 + 2x - 7 - 8x = 0

Combine like terms

x^2 + 2x - 7 - 8x = 0

x^2 - 6x - 7 = 0

x^2 - 6x - 7 = 0

a = 1

b = -6

c = -7

x = -(-6) + (-6)^2 - 4 x 1(-7)/ 2 x 1

Evaulate the Exponent

Multiply the numbers

Add the numbers

Evaluate the square root

Multiply the numbers x = 6 ± 8/2

To solve for the unknown variable, separate into two equations: one with a plus and the other with a minus.

x = 6 + 8/2

x = 6 - 8/2

Rearrange and isolate the variable to find each solution

x = 7

x = -1

You might be interested in
Pleas help me find the answer and show the work to this question
lions [1.4K]

Answer:

Leg\ 1 = 8

Leg\ 2 = 15

Step-by-step explanation:

Given: See Attachment

Required

Determine the length of the legs

To do this, we apply Pythagoras theorem.

Hyp^2 = Adj^2 + Opp^2

In this case:

17^2 = x^2 + (2x- 1)^2

Open Bracket

17^2 = x^2 + 4x^2- 2x-2x + 1

17^2 = 5x^2 - 4x + 1

289= 5x^2 - 4x + 1

Collect Like Terms

5x^2 - 4x + 1 - 289 = 0

5x^2 - 4x - 288 = 0

Solving using quadratic formula:

x = \frac{-b\±\sqrt{b^2 - 4ac}}{2a}

So:

x = 8 or x = -7.2

Since, x can't be negative, then:

x = 8

One of the leg is:

Leg\ 1 = x

Leg\ 1 = 8

Leg\ 2 = 2x - 1

Leg\ 2 = 2*8 - 1

Leg\ 2 = 16 - 1

Leg\ 2 = 15

6 0
2 years ago
Suppose a parabola has an axis of symmetry at x=-5, a maximum height of 9, and passes through the point (-7,1). Write the equati
Nutka1998 [239]

the parabola has maximum at 9, meaning is a vertical parabola and it opens downwards.

it has a symmetry at x = -5, namely its vertex's x-coordinate is -5.

check the picture below.

so then, we can pretty much tell its vertex is at (-5 , 9), and we also know it passes through (-7, 1)


\bf ~~~~~~\textit{parabola vertex form} \\\\ \begin{array}{llll} y=a(x- h)^2+ k\qquad \leftarrow \textit{using this one}\\\\ x=a(y- k)^2+ h \end{array} \qquad\qquad vertex~~(\stackrel{}{ h},\stackrel{}{ k}) \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ \begin{cases} h=-5\\ k=9 \end{cases}\implies y=a[x-(-5)]^2+9\implies y=a(x+5)^2+9


\bf \textit{we also know that } \begin{cases} x=-7\\ y=1 \end{cases}\implies 1=a(-7+5)^2+9 \\\\\\ -8=a(-2)^2\implies -8=4a\implies \cfrac{-8}{4}=a\implies -2=a \\\\[-0.35em] ~\dotfill\\\\ ~\hfill y=-2(x+5)^2+9~\hfill

7 0
3 years ago
If y = 2x2 – 4x, what is the value of y when x equals 5. <br> A.10 <br> B.30 <br> C.80 <br> D.480
Ainat [17]

Answer:

The value of y in the given equation is B. 30.

Step-by-step explanation:

y = 2x² - 4x             x = 5

y = 2(5)² - 4(5)        Plug 5 in for x

y = 2(25) - 20         Square 5 and multiply 4 by 5

y = 50 - 20             Multiply 2 by 25

y = 30

Hope this helps,

❤<em>A.W.E.</em><u><em>S.W.A.N.</em></u>❤

6 0
3 years ago
» Alexander has some watermelons. He gathers 13 more watermelons. He now has 62 watermelons.
Vilka [71]
Yeah but what is the question?
3 0
2 years ago
PLEASEEEE HELP FOR BRAINLIST!!!!!!!!!
AysviL [449]

Same thing as before!

First, we can get rid of d(x) simply by looking at it because we can tell it's linear (it's a straight line). If we look at the table, we can see a(x) is also linear because it has a steady rate of growth. b(x) and c(x) both represent exponential growth. The curved shape of b(x) shows us this is exponential growth, and the exponent in c(x) tells us it's also exponential.

8 0
2 years ago
Other questions:
  • Dominique wants to use the distributive property to find the value of 15·37+15·63 mentally. Which expression can she use?
    8·2 answers
  • Lisa used 10 centimeters of tape to wrap 5 presents. How many presents did Lisa wrap if she used 34 centimeters of tape? Assume
    10·1 answer
  • Janie has $180. She spends 50% of her money on a new pair of ice skates. How much does she spend on ice skates?
    14·2 answers
  • The length of a rectangle is 3 m longer than its width.
    12·1 answer
  • A _____________ is the information sent to a function in python
    6·1 answer
  • Can you guys help me out on this? I'm still learning sign, cosign, and tangent :)
    13·1 answer
  • An art collage includes a red paper triangle with one side length of 3.4 inches and a second side length of 8.1 inches.
    15·1 answer
  • PLEASE HELP!!!! I NEED TO GET THIS DONE!!!
    8·1 answer
  • How should the decimal point in 0.937 change to get the correct answer to 0.937 ÷ 10²?
    5·1 answer
  • Use the function y = 200 tan x on the interval 0 &lt; x &lt; 141. Complete the ordered pair (xº, 0). Round your answer to the
    14·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!