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3 years ago

Please help, thank you!

Mathematics

2 answers:

7nadin3 [17]3 years ago

5 0

Answer:

630

try solving it the first person's answer is correct

shutvik [7]3 years ago

3 0

65 x6 = 390
80 x 3= 240

390+240 = 630

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100 POINTS+BRAINLIEST 8TH GRADE MATH PT 2: Word problem involving algebraic equations on them-As usual please explain the steps

ikadub [295]

Answer:

$\sf a. \quad \dfrac{21}{10+x}+\dfrac{21}{10-x}=5$

Step-by-step explanation:

Formula for calculating speed:

$\boxed{\sf Speed=\dfrac{Distance}{Time}}$

Therefore:

$\boxed{\sf Time=\dfrac{Distance}{Speed}}$

Given values:

x = the current (in mph)
Speed = 10 mph
Distance = 21 miles
Total time = 5 hours

If the boat is traveling downstream, the current (x mph) will be pushing the boat faster, and so the boat's speed will increase by x mph.

Therefore, the expression for the time it takes for the boat to travel downstream is:

$\sf Time\:(downstream)=\dfrac{21}{10+x}$

If the boat is traveling upstream, the current (x mph) will be pushing against the boat and so the boat's speed will decrease by x mph.

Therefore, the expression for the time it takes for the boat to travel upstream is:

$\sf Time\:(upstream)=\dfrac{21}{10-x}$

Therefore, if the total time it takes to travel downstream and upstream is 5 hours:

$\implies \sf \dfrac{21}{10+x}+\dfrac{21}{10-x}=5$

To solve for x:

$\implies \sf \dfrac{21}{10+x}+\dfrac{21}{10-x}=5$

$\implies \sf \dfrac{21(10-x)}{(10+x)(10-x)}+\dfrac{21(10+x)}{(10-x)(10+x)}=5$

$\implies \sf \dfrac{21(10-x)+21(10+x)}{(10+x)(10-x)}=5$

$\implies \sf21(10-x)+21(10+x)=5(10+x)(10-x)$

$\implies \sf 210-21x+210+21x=5(100-10x+10x-x^2)$

$\implies \sf 420=500-5x^2$

$\implies \sf 5x^2=80$

$\implies \sf x^2=16$

$\implies \sf x=\pm4$

Therefore, the rate of the current is 4 mph.

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2 years ago

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I need help ASAP!! PLEASE EXPLAIN YOUR ANSWER

mezya [45]

Answer:

600

Step-by-step explanation:

Volume of cuboid = l x w x h

length = 12

width = 10

height = 5

12 x 10 x 5 = 600 yd^3

answered by g a u t h m a t h

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3 years ago

What is the vertex of the function x2 - 14x - 95 = 0?

Katarina [22]

The vertex is (7, -144)

To find it:

x = -b/2a so x = -(-14)/2*1 = x = 14/2 = 7

Plug 7 for x and find y

7^2 - 14 * 7 - 95 = -144

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Otrada [13]

Nonlinear because y is squared

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3 years ago

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Oksana_A [137]

Answer:

540 degrees

Step-by-step explanation:

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