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cricket20 [7]
3 years ago
7

What are the zeros of the function f(x)=x^2-2x-15?

Mathematics
2 answers:
Virty [35]3 years ago
7 0
F(x) = x² - 2x - 15
x = <u>-(-2) +/- √((-2)² - 4(1)(-15))</u>
                        2(1)
x = <u>2 +/- √(4 + 60)</u>
                 2
x = <u>2 +/- √(64)
</u>             2<u>
</u>x = <u>2 +/- 8
</u>           2<u>
</u>x = 1 <u>+</u> 4<u>
</u>x = 1 + 4      x = 1<u /> - 4<u>
</u>x = 5            x = -3<u>
</u>
valkas [14]3 years ago
6 0
To find the zeros of this function, we must first set the entire function equal to 0

f(x) = x² - 2x - 15 = 0

Since this is a quadratic function, we must use the quadratic formula, which is:

\frac{-b +/-  \sqrt{b^{2} - 4(a)(c) } }{2a}

Let's assign a, b, and c using our first function
x² means a = 1 (because it could be written as 1x²)
-2x means b = -2
-15 means c = -15

Now let's plug those in:

\frac{-(-2) +/- \sqrt{(-2)^{2} - 4(1)(-15) } }{2(1)}

which simplifies to:

\frac{2 +/- \sqrt{(4 + 60} }{2}

Simplified further:

\frac{2 +/- \sqrt{(64} }{2}
\frac{2 +/- 8 }{2}
And divide it by the 2 on the bottom gives us:

2 +/- 4

2+4 = 6
2-4 = -2

So the zeros of this function are -2 and 6
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Suppose your current electricity meter reading is 25,789 kWh, and the reading on your last bill was 25,350 kWh. If you are charg
Brrunno [24]

The amount of bill is $43.15

Step-by-step explanation:

Given,

Current meter reading = 25,789 kWh

Reading on last bill = 25,350 kWh

Reading for the month = Current meter reading - Last month bill reading

Reading for the month = 25789 - 25350 = 439kWh

Cost per kWh = $0.0983

Cost of 439 kWh = 0.0983*439 = $43.1537

Rounding off to nearest hundredth

Cost of 439 kWh = $43.15

The amount of bill is $43.15

Keywords: subtraction, multiplication

Learn more about subtraction at:

  • brainly.com/question/11175936
  • brainly.com/question/11203617

#LearnwithBrainly

8 0
3 years ago
Need help with this asap
valentina_108 [34]

Answer: the first one is exponential and the second one is function

6 0
3 years ago
20×+4=4(5x+1) how many solution are in this equation
Tomtit [17]

Simplify both sides of the equation

(20)(4)= 4(5x+1)

Simplify

80 = 20x+4

Flip the equation

20x+4 = 80

Subtract 4 from both sides

20x+4-4 = 80-4

20x = 76

Divide both sides by 20

20x/20 = 76/20

x= 3.8


There is one solution in this equation

7 0
4 years ago
General admission tickets to the fair cost $3.50 per person ride passes cost an additional $5.50 per person parking costs $6 for
Ghella [55]
5, 3.50+5.50= 9 per person 6 parking so 51-6 for parking = 45 and 45/9= 5
8 0
3 years ago
an outdoor deck is 7 feet wide the perimeter of the deck is 64 feet what is the length of the deck use the numbers to write an e
ycow [4]
Answer: 25

Equation:
2(7)+2(x)=64
14+2x=64
2x=64
X=25

Hope this helps :)
5 0
3 years ago
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