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2 years ago

Solve for x, where x > 0 and 84x(x + 2) = 90-13x. Express your answer as a simplified common fraction.

Mathematics

1 answer:

icang [17]2 years ago

7 0

84x(x+2) = 84x² + 168x

84x² + 168x = 90 - 13x

84x² +181x - 90 = 0

bhaskara formula

$\frac{-181+-\sqrt{181^{2}- 4.84.(-90) } }{168 } }$

$\frac{-181+-\sqrt{32.761 +30.240} }{168}$

$\frac{-181+-251}{168}$

since its a positive number, we can't use the minus

so, $\frac{70}{168}$

they're both dividable by 14, so

x = $\frac{5}{12}$ is your answer

hope it helps :)

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samantha threw an apple out of a window from the tenth floor of her appartment building. the equation y = -16t^2+120 can be used

ella [17]

Answer:
time taken = 2.74 seconds

Explanation:
We are given that:
y = -16t² + 120 models the situation where:
y is the floor number
t is the time taken for the apple to hit the ground

We are also given that the floor number (y) is 10. Therefore, all we have to do is substitute with y in the above equation and solve for the time t as follows:
y = -16t² + 120
10 = -16t² + 120
120 - 10 = 16t²
110 = 16t²
t² = 110/16
t² = 6.875
either t = 2.74 seconds ..........> accepted
or t = -2.74 seconds .........> rejected as time cannot be in negative

Hope this helps :)

5 0

2 years ago

In a certain clothing store, 4 shirts and 6 ties cost $70, and 2 shirts and 4 ties cost $42. What is the cost of each tie?

Oksanka [162]

Answer:

Step-by-step explanation:

Your two equations are ...

4s +6t = 70
2s +4t = 42

Double the second equation and subtract the first:

2(2s +4t) -(4s +6t) = 2(42) -(70)

2t = 14 . . . . . simplify

t = 7 . . . . . . . divide by 2

The cost of each tie is $7.

3 0

3 years ago

3х + 2y = 2 y = 4 Substitution

Pavel [41]

Answer:

x=-2

Step-by-step explanation:

hi! let's plug in 4 for y in the equation.

3x+2(4)=2

3x+8=2

3x=-6

x=-2

7 0

3 years ago

Read 2 more answers

A and b are positive integers and a–b = 3. Evaluate the following: 27^ (1/3 b)/9^ (1/2 a)

maxonik [38]

Answer:

1/27

Step-by-step explanation:

27^(b/3)/9^(a/2) = (27^(1/3))^b/(9^(1/2))^a = (3^b)/(3^a) = 3^(b-a)

= 3^(-(a-b)) = 3^-3 = 1/3^3 = 1/27

5 0

2 years ago

A rhombus is cut along the diagonals to make four triangles. Which three statements are correct for any rhombus? 1) All four tri

Nikolay [14]

Answer:

1). All four triangles are right-angled.

3.) All four triangles are congruent.

4) Area of a rhombus = 4 x area of one triangle.

Step-by-step explanation:

If a rhombus is cut into four triangles using diagonals, the three statements that would apply to any rhombus would be that 'all those four triangles would be right-angled,' 'the triangles would be congruent to one another,' and 'area of one triangle * 4 would be equal to the area of the rhombus.'

As we know, the diagonals bisect one another in a rhombus at 90° and the angles opposite to one another are equal. This proves that all four triangles constructed through the diagonals would be ≅ through SSS congruency and perpendicular to one another because the corresponding edges of the congruent triangles are also ≅ . Since the rhombus is divided into four equal parts, the area of one triangle into four would be equals to the area of the rhombus. Thus, options 1, 3, and 4 are the correct answers.

8 0

2 years ago