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3 years ago

I don’t understand this problem and need help!

Mathematics

1 answer:

butalik [34]3 years ago

7 0

Answer:

see explanation

Step-by-step explanation:

Since AB and BC are perpendicular, then

∠ABC = 90° and

∠ABD + ∠DBC = ∠ABC ← substitute values

3r + 5 + 5r - 27 = 90, that is

8r - 22 = 90 ( add 22 to both sides )

8r = 112 ( divide both sides by 8 )

r = 14

Hence

∠ABD = 3r + 5 = (3 × 14) + 5 = 42 + 5 = 47°

∠DBC = 5r - 27 = (5 × 14) - 27 = 70 - 27 = 43°

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Ben, Tim, and Sam have to do a certain job. Ben can finish the job in 5 hours. Tim can finish the job in 6 hours. Sam can finish

Brut [27]

x is 7.5 hours

Step-by-step explanation:

Ben, Tim, and Sam have to do a certain job

Ben can finish the job in 5 hours
Tim can finish the job in 6 hours
Sam can finish the job in x hours
The three of them can finish the job in 2 hours if they work together

We need to find x

∵ Ben can finish the job in 5 hours

∴ The rate of Ben = $\frac{1}{5}$

∵ Tim can finish the job in 6 hours

∴ The rate of Tim = $\frac{1}{6}$

∵ Sam can finish the job in x hours

∴ The rate of Sam = $\frac{1}{x}$

They will working together to finish the job in two hours, that means the sum of their rate is equal to 1/2

∵ They can finish the job in 2 hours if they work together

∴ $\frac{1}{5}+\frac{1}{6}+\frac{1}{x}=\frac{1}{2}$

To add the fractions find the LCM for all denominators to make all fractions with same denominators

∵ The LCM of 5, 6 ans x is (5 × 6 × x) = 30 x,

- Divide it by each denominator to find the new numerators

∵ 30 x ÷ 5 = 6 x , 30 x ÷ 6 = 5 x , 30 x ÷ x = 30

- Change all the denominators to 30 x and then write the new

numerators of each fraction

∴ $\frac{6x}{30x}+\frac{5x}{30x}+\frac{30}{30x}=\frac{1}{2}$

Add the numerators and put the sum over 30 x

∵ $\frac{11x+30}{30x}=\frac{1}{2}$

- By using cross multiplication

∴ 2(11 x + 30) = 1(30 x)

- Simplify the both sides

∴ 22 x + 60 = 30 x

- Subtract 22 x from both sides

∴ 60 = 8 x

- Divide both sides by 8

∴ 7.5 = x

∴ The value of x is 7.5 hours

x is 7.5 hours

Learn more:

You can learn more about the word problems in brainly.com/question/10712420

#LearnwithBrainly

5 0

3 years ago

At a game show, there are three doors marked 1, 2, and 3. A contestant is allowed to select one of three keys labeled A, B, and

sineoko [7]

Answer:

It is A

Step-by-step explanation:

8 0

3 years ago

Read 2 more answers

How many solutions are there in the given equation?<br> y = 2x² + 6x + 4

tigry1 [53]

Step-by-step explanation:

Use the quadratic formula

−

√

x=\frac{-{\color{#e8710a}{b}} \pm \sqrt{{\color{#e8710a}{b}}^{2}-4{\color{#c92786}{a}}{\color{#129eaf}{c}}}}{2{\color{#c92786}{a}}}

x=2a−b±b2−4ac

Once in standard form, identify a, b and c from the original equation and plug them into the quadratic formula.

2x^{2}+6x+4=0

2x2+6x+4=0

a={\color{#c92786}{2}}

a=2

b={\color{#e8710a}{6}}

b=6

c={\color{#129eaf}{4}}

c=4

−

⋅

√

⋅

x=\frac{-{\color{#e8710a}{6}} \pm \sqrt{{\color{#e8710a}{6}}^{2}-4 \cdot {\color{#c92786}{2}} \cdot {\color{#129eaf}{4}}}}{2 \cdot {\color{#c92786}{2}}}

x=2⋅2−6±62−4⋅2⋅4

brainliest and follow and thanks

8 0

2 years ago

Solve for C.<br> -5/8c=20

iris [78.8K]

-5/8c = 20....multiply both sides by -8/5 (this cancels out the -5/8 on the left
c = 20(-8/5)
c = -160/5
c = - 32

check..
-5/8(-32) = 20
160/8 = 20
20 = 20 (correct)

so c = -32

8 0

3 years ago

ANSWER ASAPPPP FORR BRAINLIEST

miv72 [106K]

Answer: the first one

Step-by-step explanation:

4 0

3 years ago