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3 years ago

F(x)=x^2-3x-15 what’s the root

Mathematics

1 answer:

Anestetic [448]3 years ago

8 0

Answer:

There are two roots:

(3 + √69)/2 and (3 - √69)/2

Step-by-step explanation:

Use the quadratic equation to solve this...

x = [-b ± √(b² - 4ac)]/(2a)

Here, a = 1, b = -3, and c = -15, plug them in and simplify

x =([-(-3) ± √[(-3)² - 4(1)(-15)])/[2(1)]

x = (3 ± √[9 - (-60)])/2

x = (3 ± √69)/2

x = (3 + √69)/2 and x = (3 - √69)/2

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What are the solutions of the quadratic equation (x + 3)(x +3) = 49? Ax = -2 and x = -16 Bx = 2 and x = -10 Cx = 4 and x = -10 D

Ivahew [28]

Answer:

4 and -10

Step-by-step explanation:

$\displaystyle (x + 3)(x +3) = 49 \\ x^2+3x+3x+9=49 \\ x^2 +6x+9=49 \\ x^2 + 6x + 9 - 49 = 0 \\x^2+6x-40=0 \\\\ \Delta=b^2-4ac \\ \Delta=6^2-4 \cdot 1 \cdot (-40) \\ \Delta=36+160 \\ \Delta=196 \\ \\ X_{1,2}=\frac{-b \pm \sqrt{\Delta} }{2a} \\ \\ X_1=\frac{-b+\sqrt{\Delta} }{2a} = \frac{-6+14}{2} = \frac{8}{2}=4 \\ \\ X_2=\frac{-b-\sqrt{\Delta} }{2a} = \frac{-6-14}{2}=\frac{-20}{2} = -10$

4 0

3 years ago

PLEASE HELP NO SCAM LINK OR REPORTED :) THANKS

Naya [18.7K]

Answer: b

Step-by-step explanation:

2x is x doubled

and then add 5 to the product

6 0

3 years ago

A rectangular playground is to be fenced off and divided in two by another fence parallel to one side of the playground. Seven h

Arisa [49]

Answer:

Step-by-step explanation:

Suppose the dimensions of the playground are x and y.

The total amount of the fence used is given and it is 780 ft. In terms of x and y this would be 3x+2y=780 (we add 3x because we want it to be cut in the middle). Therefore, y= 780/2-3/2x. Now, the total area (A )to be fenced is

A=x*y= x*(390-3/2x)=-3/2 x^2+390x

Calculating the derivative of A and setting it equals to 0 to find the maximum

A'= -3x+390=0

This yields x=130.

Therefore y=780/2-3/2*130=195

Thus, the maximum area is 130*195=25,350ft^2

8 0

3 years ago

What is the measure of all angles. HELP ASAP! Will someone answer this for me like right now. Thanks

mel-nik [20]

Answer:

∠ ABC = ∠ DBE = 65°

∠ ABD = ∠ CBE = 115°

Step-by-step explanation:

See the diagram attached to this question.

Now, ∠ ABC and ∠ DBE are two vertically opposite angles.

So, 3x + 38 = 5x + 20

⇒ 2x = 18

⇒ x = 9

So, ∠ ABC = ∠ DBE = 3(9) + 38 = 65° (Answer)

Again, ∠ ABC and ∠ ABD are supplementary angles.

Then, ∠ ABC + ∠ ABD = 180°

⇒ ∠ ABD = 180° - 65° = 115°

And ∠ ABD = ∠ CBE {Vertically opposite angles}

So, ∠ ABD = ∠ CBE = 115° (Answer)

6 0

4 years ago

A rectangle has an area of 96 cm2 The length of the rectangle is 4 cm longer than the width. Work out the length and width of th

Svetach [21]

Area of a rectangle: 2(L+W)
length: 4+W

Area: 2(4+W) + 2W = 96
8+2W+2W = 96
8+4W = 96
4W = 88
W= 22cm

Calculate for length: 2L + 2(22) = 96
2L + 44 = 96
2L = 52
L = 26cm

• The length is 26cm and width is 22 cm.

3 0

4 years ago