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slega [8]
3 years ago
13

What are the zeros of the quadratic function f(x) = 2x2 + 8x – 3?

Mathematics
1 answer:
jenyasd209 [6]3 years ago
7 0

Answer:

  x=-2-\sqrt{\dfrac{11}{2}}\ \text{and}\ x=-2+\sqrt{\dfrac{11}{2}}

Step-by-step explanation:

My favorite way to go at this is to look at a graph. It shows the vertex at (-2, -11). Since the leading coefficient is 2, this means the roots are ...

  -2\pm\sqrt{\dfrac{11}{2}}

where the 2 in the denominator of the radical is the leading coefficient.

__

You can also use other clues:

  • the axis of symmetry is -b/(2a) = -8/(2(2)) = -2, so answer choices C and D don't work
  • the single change in sign in the coefficients (+ + -) tells you there is one positive real root, so answer choice B doesn't work.

The first answer choice is the only one with values symmetrical about -2 and one of them positive.

__

You may be expected to use the quadratic formula:

  x=\dfrac{-b\pm\sqrt{b^-4ac}}{2a}=\dfrac{-8\pm\sqrt{8^2-4(2)(-3)}}{2(2)}\\\\=\dfrac{-8}{4}\pm\dfrac{\sqrt{88}}{4}=-2\pm\sqrt{\dfrac{11}{2}}

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Which equation can be used to solve for the unknown number? Seven less than a number is thirteen.
zysi [14]

Answer:

n-7=13

Step-by-step explanation:

We need to find an equation that represents the expression: "Seven less than a number is thirteen".

It means that a number minus 7 equals 13. So, the correct option is: n-7=13

Bonus: Solving for 'n' we have that n=20.

So, Seven less than 20 equals 13!!

7 0
3 years ago
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Find the missing value given (-1,7)(-3,d) m= 6 HELP ASAP WILL MAKE BRAINLEST
-Dominant- [34]

Answer:

d= -5

Step-by-step explanation:

The slope of a line is found by finding the ratio of change is y values to change is x values

m=y_2-y_1/x_2-x_1

The points on the line have coordinates at: (-1,7) (-3,d)

where ;

y_2=d, y_1=7,x_2=-3,x_1=-1,m=6

Applying the formula with values as;

6=\frac{d-7}{-3--1} \\\\6=\frac{d-7}{-3+1} \\\\6=\frac{d-7}{-2} \\\\6*-2=d-7\\\\-12=d-7\\\\-12+7=d\\\\-5=d

The value of d = -5

The coordinates of the points  (-1,7) (-3,-5)

6 0
3 years ago
Plssss helppppp!!!!!!!!!
Ira Lisetskai [31]

Answer:

it is two because one apple plus one apple equals two

it is 2

8 0
3 years ago
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Let f(x) = 1/x. Find a number b so that the average rate of change of f on the interval
Bezzdna [24]

Answer:

huh try multiplying

Step-by-step explanation:

6 0
3 years ago
Please help i dont understand
Elena L [17]

Answer:

I think number one is 19

Step-by-step explanation:

8 0
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