3 years ago

Please help meeeeeeeeeee

Mathematics

1 answer:

anzhelika [568]3 years ago

4 0

The Third one hope that helped <3

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Can someone answer these questions ? thank you

Naya [18.7K]

Answer:

Step-by-step explanation:

12a)To rationalize the denominator, multiply the denominator and numerator by √5.

$\frac{15}{\sqrt{5}}=\frac{15*\sqrt{5}}{\sqrt{5}*\sqrt{5}}\\\\=\frac{15\sqrt{5}}{5}\\\\=3\sqrt{5}$

b) (a+b)² = a² + 2ab + b²

(1 +√3)² = 1² + 2*1*√3 + (√3)²

= 1 + 2√3 + 3

= 4 + 2√3

a = 4 ; b =2

13) (a + b)(a - b) = a² - b²

$\frac{(6-\sqrt{5})(6+\sqrt{5})}{\sqrt{31}}=\frac{6^{2}-(\sqrt{5})^{2}}{\sqrt{31}}\\\\ =\frac{36-5}{\sqrt{31}}\\\\=\frac{31}{\sqrt{31}}\\\\=\frac{31*\sqrt{31}}{\sqrt{31}*\sqrt{31}}\\\\=\frac{31\sqrt{31}}{31}\\\\=\sqrt{31}$

5 0

4 years ago

Write an expression that is equivalent to 4n – 12 + 8y + (-3n).

Dimas [21]

It would be 1n - 12 + 8y.
4n - 3n = 1n
12 + 8y don’t mix so we can leave it.
Therefore: 1n - 12 + 8y

7 0

3 years ago

one eighth of the brass instruments are tubas. if there are 240 instruments in the band, how many are tubas?

Andrej [43]

Just do 240 times 1/8 which is the same thing as 240/8, which is 30

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3 years ago

The area of the sector of a circle with a radius of 8 centimeters is 125.6 square centimeters. The estimated value of Pi is 3.14

elena55 [62]

Hello there!

The correct answer is C. 225.

Hope This Helps You!
Good Luck :)

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3 years ago

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Anna71 [15]

Answer:

Step-by-step explanation:

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2 years ago